I can't remember if it was KT66 or 88, but I heard them in a guys Recto live and recorded. Sounds amazing. I should have investigated as I could never get my Rectos to sound that good. I only replaced with Mesa tubes.
Hey Steve - Which ones did you use?
I'm trying to make a point by asking the question. A $400 amp is not made in USA. A $4K amp is not 100% made in the USA. It might be really close but be realistic. And if it's not, does it really matter? A great design, built in the US, backed by good guys with a great warranty... you should...
Glad to hear you're keeping the QR. I'd say amp #2 needs to be drastically different as far as sounds and features.
Try and play a bunch of em if you can.
I'll add Bogner Uber and Diezel Hagen since nobody mentioned yet.