I bought a pair of Westinghouse 6SN7 tall bottle tubes based on your rec, they got here yesterday. I'll give them a go this weekend. And I totally agree, the new production Tung Sol tubes are quiet and rugged but merely "good" and not great sounding.
So Psvane is in the top spot, interesting!
Man, the tube rolling possibilities in this amp are astonishing. Makes me want to buy more tubes just to do some shootouts!
I should mention, since my first post in listing the output tubes I have, I've since added some metal clad Sylvania and RCA 6V6 tubes, a pair of Siemens (made by Mullard) EL34 tubes, Gold Lion EL84 tubes, and CBS 6L6 metal clad tubes.
I'm stoked to get the Siemens EL34s as that will be a nice reference set of tubes to compare the others to. I have new production Mullard EL34, Svetlana EL34, Electro Harmonix EL34 and the Gold Lion KT77 (not exactly an EL34 but closer than any other tubes I have). Might be fun to see how these newer production tubes stack up against a high quality NOS set of tubes.
After that, it'd be cool to have a "EL84 shootout" with the Phillips Miniwatt and Gold Lion I already have, maybe get a Psvane EL84 to throw into the mix as well.
Same with KT66's. As of right now, I know the GL KT66 is my favorite current production pentode tube, but I've never heard the Black Treasure KT66-z so that'd be fun to try out.
Only problem is time! IME good quality tubes take about 100 hours to even come close to sounding their best, you can't just drop a totally fresh tube into the amp and expect to hear it at its best.