Well, I find myself here because I have a range of NOS and apparently I can only tell you about after contributing, which probably doesn't make sense as I am a guitarist and really whilst I like Valve Amps for both Guitars and Audio, I am not so into Valve Hi Fi that I want to sit and chat on a forum, power to you, I like forums.
Sorry to be brutally honest,
I have some Holy Grail Tubes and given you guys are likely to be into it I want to tell you about them.
Mean while I will post some interesting articles about Amp builds and maybe that will help address some antiquated rules that removes your opportunity but manages to tick a box on someones "this is a good idea " list