Hi Charles - Thank you for your guidance on all of those tubes, many of which I knew nothing about. Completely agree that listening in my amp and in my system is the best way to go. Hopefully I can find "the tube" without too much $$$ lost to trial and error.
I suppose, since I started this thread, it is "ok" for me to briefly sidetrack it to share something of possible interest to you and others. A couple of months ago I first heard the most remarkable speaker, the first speaker that actually makes me want to replace my Solovox. It is another one from Auditorium-23 - the Cinema Hommage. If you ever get the chance to hear this speaker, I am confident you will be impressed. For me, it has all of the things I love about the Shindo Latour, the Solovox, and the Vandersteen 7 - all embodied in one speaker that is actually smaller than any of those three. It is quite costly and currently has a low WAF, but I remain hopeful!