Welcome!

Just to clarify, I am not completely sure what you are asking about clean headroom. But I will comment on the Yeti 100w. I've had mine for about a year and am totally blown away by this amp. Simply amazing!

Here is a quick review/comments/description:
Plexi mode: Excellent plexi tones. Hendrix, ACDC, Molly Hatchet, up to VH (with humbuckers). This mode is amazing. The gain is obviously British voiced, but slightly different than stock Marshalls. Personally, it's exactly what I wanted. I own a few Marshalls which are great, but they always were just slightly different than what I wanted. This has the tone that I was searching for.

80's mode: this kicks in some diode clipping. Think of this as a plexi with a dirt pedal in front boosting it. Tons of gain here. I don't use this mode much, if at all, but every time I experiment I always like it. No problem with VH, Ratt, Docken....etc.

Modern mode: even more gain, think distortion pedal in front of a plexi. I never use this mode, but don't take that as it doesn't sound good. It sounds great, it's just way more gain than I use.

I have 2 plexis which I love, but I only love them when they are cranked. at low volumes they lack "umph". The Yeti sounds great at ALL volumes. The master volume works great. Although I must admit it sounds better cranked, but I can use it at bedroom volumes and still love the tone. Also...and this is very important to me. I play every weekend in different rooms. This is the most consistent sounding amp room to room that I have ever seen! My Marshalls were finicky room to room, the Yeti sounds the same every time with very little tweaking. Lastly, the loop on mine is amazing. I have delay, pitch shift/harmonizer, and lead boost in my loop and it is amazing. I've heard others complain about loops...not sure if I got lucky or if Ceriatone has the passive loop thing figured out. All I can say is I love mine.

Now to be 100% fair, I will also mention some nit picks. First, clean tone. I haven't found what I would call a "good" clean tone. I wouldn't use this amp as a clean platform for pedals. But I also must point out that I got this amp for it's gain tones so the lack of clean is no issue for me. Next, this amp will compress quicker than typical Marshalls, even in plexi mode. I've learned how to adjust to it so it too is a non issue for me. Just know it may take a little tweaking to get your tone, and control the compression (if desired).

All I can say is I would recommend this amp to EVERYONE who is searching for British tones, versatility, and usability. The price for what you get is totally worth every penny! If you have specific questions how I run mine live, feel free to hit me up. Like I said, this thing sounds great at whisper volumes, and cranked up.

Go ahead and make your purchase and dedicate your next record to me

Excellent, You will love it! Also, if you are in the states, you will need to pay extra charge upon delivery. I forget exactly what it was, international something. UPS collected it at the door, around $25 depending on where you are.

All of my FX are pedals. Here is my signal chain:
Guitar > TU2 > Wah > MXR micro flange > MXR micro chorus > MXR script 90 phase > Maxon 808 > Fulltone Fatboost > MXR super badass distortion > Wampler Plextortion > Amp > Marshall 1960hw (a or b) cab. Cab has 30w greenbacks, 55Hz.

Loop send > Boss Harmonist PS-6 > Boss DD7 > Boss feedback/booster > Loop return

I am somewhat a pedal junkie The front end pedals change about once a month. I run my amp in plexi mode. Gain set similar to Free/Foghat/ACDC. I roll my guitar volume for clean tones. My main tone is the fatboost and 808 on in front, both set to clean boost(drive way down). I add the badass for higher gain/brighter distortion like VH. Or, I turn those off and use the wampler by itself for 80s tones. I should note that I "could' remove those front end OD's and dial those tones in just with the amp, but I play in a cover band so I need a little more versatility than a single channel amp provides.

The Yeti takes the modulation pedals in front very, very well. I used to run the PS-6 in front of my Marshalls and it was ok at lower distortion levels but would crap out at higher gains. But in the Yeti loop, it never sounded better even with higher gain levels. Same with the DD7. This was an unexpected surprise for me. I have read that it is best to use buffered bypass pedals in a loop, which I "think" Boss pedals are. Keep that in mind. I can't confirm that but there may be something to it?

I can't say enough good things about this amp. Oh yeah, when you get a chance, pop the hood and take a look at the hand wiring. Absolutely beautiful! This really is a great amp. Play with the bright switches/eq. You can make this thing as bright or dark as you want. One other nice surprise was the bottom end. Tons of usable bottom end. I always felt my marshalls lacked that at low volumes. Not the case with the Yeti.

Oh yeah, this thing makes most of my OD's sound great in front of the dirty Yeti. I used to hate that Wampler Plextortion. But infront of dirty Yeti, it is currently my favorite 80's sounding pedal. It actually sounds better than my Pinnacle...which is the best sounding dirt pedal I have ever heard. (It also sounds good infront).

Once you get it, post some comment and set ups. I love to see how others are running their rigs.

I thought about getting a C lator for my Marshalls. You may or may not need it but I think it's still a good tool to have. Let me know how that works for you. I also like my modulation before dirt. The only exception would be that harmony pedal (PS6). That thing sounds amazing in the loop.

Nik was great to deal with. I swear that guy never sleeps. Don't hesitate to ask him questions after you get it. I would hit him up with set up questions and he was always very helpful.

Yep, turn the master all the way up and you now have an old school plexi. Gain 1 and 2 act like the normal and high volumes on a plexi. Put in your ear plugs!

Don't buy one yet.  The master volume works extremely well. Keep in mind that once you start cooking the power stage, you will lose most of your headroom to boost a lead. That's why this amp is perfect for what I do live.

I totally get that nothing sounds like a screaming power stage, but I think you will be pleasantly surprised how good the preamp stage in the Yeti sounds. No, it's not a stock 68' plexi, but it sounds freakin awesome in it's own way.

Don't forget to throw dirt pedals in front of this thing when it's already dirty. Simply amazing!

I used to run an attenuator (marshall power brake) with my plexi's. I got sick of toting it around. It sounded fine, just became a hassle. But then again, I run 2 pedal boards, and the FX loop in this thing so what's one more piece of gear ha ha.

I am running the head into a Marshall 1960hw (a or b) cab. I have both cabs, but I actually prefer the top (slant) cab. The bottom can be a bit bassy at times. I also like to have the angle pointing up at me rather than the the speakers hitting the backs of my legs on stage. Cab has 30w greenbacks, 55Hz.

To my ears, the slant just sounds better. I use the slant for both live and recording.

Ive heard good things about Germino stuff.

I play small to medium size clubs. I certainly don't need a 100w amp! But I like to the sound and I am still willing to lug around a half stack

Even in the smallest clubs, I still mic the cab. I always have been a proponent of a lower stage volume. I probably run my Yeti in plexi mode with the volume on 1-1.5. It's pretty loud at that. In fact I don't think I ever gigged with the volume at 2. In the other Era modes, yeah. You need to crank up the volume a bit more. But in plexi mode it's pretty loud. Btw, you can start to hear the power section heating up around 2-3. Man it really sounds fantastic at that but it's freakin LOUD!

Don't worry about not having enough amp. You could fill a medium to large room or an outdoor show with it easily. Or you can turn it down and let your front of house do the work and it will still sound fantastic.

I really like the greenbacks with this amp. There is so much low end in the amp, mix that with the mid bark of greenbacks and you have a really full sound. I also have a 300w marshall cab (75w speakers) here at the house but I never hooked it up. My son basically took over that cab for his 6534+ head.....which sounds amazing at what it does.

Yep, your gonna love this amp. Don't worry about buyers remorse on this purchase. Keep in touch when you get it. I am curious to hear your impressions.