I use NOS Siemens 7308s and have written about them on the tube rolling thread. They are terrific. I value them so much I switch them in and out just to limit accumulated hours so that I can enjoy them for years to come. I would guess I have around 1000 hours accumulated so far.
Nobody can ‘convince’ you to proceed it you don’t want to. I obviously have zero hesitation. Do read about and understand the correct bias jumper position to use with 6 volt tubes. Don’t just plop them in in substitute for 12AU7s without switching the bias jumper as well.
I purchased mine from Brent Jesse btw.
I will say this about Brent. My 7308s are the finest pair of 6 volt 6DJ8 variant tubes I have ever purchased. But I purchased a second pair advertised as NOS and Gm tested out at 60% of factory spec. Haven’t purchased from his again. Don’t blame the tube type for any issues.