I see there's a 5F1 Champ clone, but how about a 5C1?

The main difference of course being that it uses metal preamp tubes like a 6SJ7 just like the originals.
The reason I ask is that I have a bunch of vintage parts I'm just itching to use for a Champ/Princeton clone and want to stay away from the 12**7 tubes everyone else uses. Not that they're bad, but those old metal tubes are just cool, plus they seem to last practically forever. 
Many people also feel the 6SJ7 tubes sound much fatter and creamier than a 12AX7.

If not a whole different project, what mods would it take to use the 5F1 setup to do a 5C1 build?
The 5C1 seems like the absolute most basic Tweed style amp you could possibly build.

Cheers,
 - JJ