Hi John,
Welcome back! Sounds like you have been busy.
Please explain to the listeners why you would entrust a rare and vintage CRT to UPS? You can make up as good a story as you want. We'll listen
I have one of those 5" test CRTs as well. Sure are handy sometimes, ...even though I don't use UPS!
That's interesting about the Chinese 6SN7's. I've never seen them. I have a big box of used original quality North American manufactured 'pulls' from scrapped sets, etc. You just can't have too many of those. I use them in my audio amps too.