I’ve never dealt with Andy, but have always been impressed with his site. At least for information, Brent Jessee’s site is very useful too. That said, if I’d known what I eventually learned about the newer Sophia and Treasure Globe tubes, I’d have saved a few $K and lots of time. What I would have lost would have been learning about and listening to lots of older tubes, now all lined up across the brick base of my fire place.
Before I switched to the Treasure Globe’s, available from Rachel at Premium Vacuum tubes (Grant Fidelity), my favorites were the Sylvania 6F8G, the latter type being the original 6SN7 name, and the USAF 596 rectifier. They both do require an adapter from China or from Woo Audio (better but more expensive) though. Btw, there’s an RCA tube date guide online under the search "date codes for RCA-made tubes Ludwell Sibley" (the only thing missing is that for replacement tubes from the mid 1950s on RCA used a YY-WW on the base, where WW referred to the week of the year). Some for other brands’ are available too.