Thought this would work out well and what surprised me was how good the cab worked with a variety of amps besides my 50w HRM.  By that I really mean how the cab was great sounding in non rotating mode with the bass rotor and treble horn auto stopped facing directly forward... besides the great sounds in slow and fast rotating modes.  Highly recommended except for weight for gigging, small footprint and big sound.  Standard HRM head cab fits across top nicely.  Can't post clips...

The sound is simply outrageous in a very good way...the real Leslie cab for a real Leslie sound.  Worth every stinking penny.

@ the OP:

Your question about desiring to run most of your effects in front of the amp while putting the time based ones in the loop is interesting.  What I think would benefit you significantly is to carefully read, more than once, the manual for your model of amp and especially the manual for the c-lator.  Because I use a multi-effects processor, all of my effects go through the loop.  I don't use a C-lator on my church rig only because the type of effects processor I am running does not put out as strong of a signal as many of the 9v powered effects do.  My volume pedal is the only thing that runs in front of the amp.  It's active, and features an optical circuit instead of a potentiometer to vary the volume, and I want the varying signal strength to go to the first gain stage in the preamp.  I can't see any reason to run effects in front of the amp.   Whether you decide to use effects or not, the c-lator is pretty nice to have as part of the amp.  Worth every penny and then some.

Niiiice! 

A D-style amp can be the sweetest ever for gospel music/worship!!!  That's all you really need to know, but for a major dose of keyboard diarreah keep reading

 

After obtaining my 50w HRM with the lift neg fb mod and C-lator, I realized how nice a D-style amp would be for worship.  I was using another amp, also a boutique amp, for worship, but the amp I was using was a single channel.  It has wonderful tone, and after getting my HRM, I found that I could coax similar types of singing overdrive tones by gain knob settings on the amp I was using, a Siegmund Midnight Blues running a personal tube cocktail.

I just wanted more choices for gain/tones and I did NOT want to use a stomp box to get my OD, was looking for tube harmonics.  Many gospel recordings feature guitar players using a thin, bright and nasty solid state distortion sound, to me a big "UGH."  So I was perusing ebay and happened across a Marsh fsx-50, from Marsh Amps, an OTS type using Ceriatone boards assembled in the US with MM PT and Heyboer OT, it was listed at a BIN price a few hundy less than retail from the Marsh site.  It has the OD trim on the back panel, which I consider to be essential, as well as a half power switch that straps the power tubes into triode mode.  I asked the seller about installing lift neg fb mod and he quoted me a price increase of 35 dollars.  He wired it to the ground switch on the back panel.  So, since I have more than a hundred vintage tubes in my collection and did not want any new production tubes in the amp anyway, I asked him for no surcharge in exchange for shipping the amp tubeless and adjusting the PI trimmer for a 12ax7 having balanced sections.  So he did. 

That amp sits in the sanctuary now, with no c-lator, it goes into the sound board via a Weber MASS custom built for me with a balanced line out.  The MASS is being used as a glorified direct box, attenuation dial backed all the way off for little to no attenuation.  So no micing ever, and I control my tone going into the mixing board as well as how hot the signal is from the full tone stack that controls the line out.  Again, I used a tube cocktail from my collection for this amp, and it goes through a pair 2/12 closed back cabs in parallell running vintage HIFI speakers,  JBL/Ampex 12's and Pioneer pw-302a each cab 32 ohms, so I use the 16 ohm setting on the amp output.  With the four 12 inch cones pushing a decent amount of air, I can be heard better from the speakers themselves at distance with less stage volume, an important consideration for the other musicians and choir, and also a little less help needed from the sound board.  The cabs are pretty neutral in sound, not as bright as many guitar speakers can be.  I use a TC Elecrtronic Nova System as my f/x box running in the amp f/x loop, 4 cable hookup method, it works great without any added buffer units.  The tremolo does not sound good by itself, but works acceptably in the overall mix, FWIW.  Reverb and delay are nice. 

Finally, if you want a smooth sounding overdrive that swells in the attack or sustain like a Hammond B3 rig does, sings into blooming harmonics at usable stage volumes, two incredibly helpful links in your personal tone chain are a potless volume pedal or talented fingers on your git's volume knobs, and a decent pair of HEMP CONE speakers.  I use a Hilton Electronics volume pedal, active and top shelf quality, I got my pair of custom hemp cone speakers from a custom reconer on eBay, he guarantees that you will like his stuff.  No big manufacturor ever does that.  Search "speaker 12 hemp" on the 'bay to see what is currently offered.  Hemp cones smooth out the highs well for distorted channel settings, allowing a bit more gain in OD trim or front panel gain knob with less grit and more harmonics in the tone.  I use the hemp cone 2/12 filled oval back opening "Luke" cab from Seismic Audio with my HRM for non-church playing out, and have gotten tone compliments everywhere I have played.  The custom hemp speakers in that cab started life as 1949 vintage Altec 600b alnico units.  They cost me less than TT or Eminence units.

hope this helps...

FWIW, got my adaptors off fleabay from a seller named ayumitubes.  they fell apart pretty quickly due to lack of adhesive.  So I got myself some gel style CA glue and reglued them with a more liberal application of the new glue, they have stayed together just fine.  Bias the Sylvania units somewhere between high 30's and low 40's in your D-clone.  Bias the GE blackplates in the low 30's like you would do with el34's.  RCA blackplate 6bg6ga's have the lower wattage plates, I would not use them in a D-clone.

I saw a screaming deal on fleabay for an OTS by Marsh amps, the fsx-50 Overlord.  Uses C-tone boards, Mercury PT and Heyboer OT.  Got mine with half power switch, OD trim on back panel, and lift negative feedback switch.  'Bout tore my face off the first time I played through it in a good way a la Marshall-y tone with the negative feedback lifted, more of an effect than with the same feature on the HRM.   Like the HRM, a huge tone palette but can still do the classic smooth oozy D-style sustain.  Running GE blackplate, or Sylvania grayplate 6bg6ga's with adaptors in my OTS, wonderful sounding and once I got the adaptors, 6bg6ga's are affordable, as in cheaper than modern 6l6's with better tone IMHO. 

You are right in the ballpark, IMHO.  That is a very tight match for a quad. 

All right, that's just too much for me to take.  Meet me after church so I can kick yer butts... 

JK

...I prefer Marmite! 

Saaaaweeeeet!  Glad to hear you are enjoying the vintage old stock goodness.  I'm gonna sit and soak in a hot bathtub, listen to some blues, have a couple brews and when I get out am gonna play through those new hemp cones some more.  Man, they really suit the singing bloom of the D-style tones!

Tone report time...

The speakers finally arrived, I rear mounted them in this cab.  Using my (vintage tubed) 50w HRM w/ neg feedback lifted, 16 ohm output setting, huge, fat, smooth, oozy, with gorgeous harmonic bloom.  No bark with these.  You don't need any high pf cables between the c-lator and amp with this setup, you hear the highs but they are very smooth.  No bottom end flab, but the bottom is very big in this higher than normal volume cab, no need to use the deep switch.  At window rattling loudness tones are similar to small room volumes, very linear volume/tones relationship.  These speakers in this cab are darker than I expected, but the harmonic bloom on the long notes is truly spectacular, all strings, and all over the neck.  The cab build quality was not especially wonderful, but for the price what to expect?  This eBay seller does up some pretty Frankenstein-ly speaker recones, not a herd follower.  Does customs too.  Great packing job. 

Me likey lots...

end hijack...

Those ribbed plate 'funkens are a bit brighter and to my ears more desirable for guitar amp use than the smooth plates.  When you put them in a high gain situation, they will deliver a nice, violin-like compressed, smooth sustain.  Good for V2, PI (if decently balanced between the triodes), have one right now in my C-lator.  Sure hope you like them.  One stupid amp trick I found out, when you socket the pair power tubes in a 50 watter, swap them side for side, one way will give slightly more sustain than the other.

To the OP...

You came to a great place here, and every one of the guys that previously posted to your thread are right on.  I'm a Mesa owner as well, have a 2/12 Maverick with nary a Mesa speaker or tube in it, along with a one of a kind custom bias mod, and have several boutique amps, along with a collection of a few hundred vintage tubes, but none of my other amps are as versatile in both tones and ability to sound great from small rooms to large with the same amp like the D-style clones previously mentioned.  I have a 50w HRM with a c-lator, and a 50w OTS built by Marsh with c-tone boards that I run by itself with no fx buffer, it is also amazing in the range of tones it can do at small to large room volumes.  I'm glad to have both of these middle of the road D-style  amps.  The various switches and gain and tone controls offer an amazing tone palette.

My (as usual) unusual $.02...

New Cab Day, New Speakers Day soon...

This...

http://www.ebay.com/itm/130563019861?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

With these...

http://www.ebay.com/itm/170682321019?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

I really really like the two cabs I am using with my C-tone 50w HRM+C-lator and C-tone/Marsh OTS fsx-50 Overlord...a 2/12 semi closed back stuffed with JBL G125's, and an old possibly Gibson semi closed back 1/15 housing a vintage Jensen Vibranto, both setups are fat and lush, no ice pick.  The JBL's in their cab are brighter on top.  I also have a pre EVM 12s by Altec Lansing, the ER 12s, same frame and cone as the EV unit, liked the tight and big bottom end, but found it to be a bit too bright on top sitting in a Bedrock 651 1/12 50w combo... 

But I have been jonesing to try a pair of Altec types, and having a soft spot for vintage alnico drivers, I thought I'd give these redone 600b's a try.  Originally they were rated for around 30 watts apiece, they predate the 417 series of alnico speakers that HAD and Carlos Santana liked.  I can't post clips, but will describe how they do once they arrive and I give them some break in time in the new cab.  This eBay seller re-does up a lot of one off speakers for guitar, most I have seen of his listed on eBay are done up in hemp.  I like the fact that he is willing to take back if the buyer doesn't like them, know any of the big mfg's that do that?

With my Ceriatone/Marsh 50wOTS In front: Area 51 Wah, Keith Hilton low profile active volume pedal.  In the loop: TC electronics Nova system pedal.  The tremolo setting in that pedal is the worst sounding trem I have ever heard.  It works okay within the band mix, but by itself it sounds like...I won't say it!. 

With my Ceriatone 50w HRM, the same except the TC unit goes in and out of a Ceriatone C-lator, which in turn goes in and out of the amp's fx loop.   I don't do the long cable trick for the C-Lator.