[TV MAN]

Sounds like a pretty nice set! If it's all original, it's probably a low hour. Not sure what to tell you on the tube test, My testers don't have that, but have a bunch of other stuff. It does sound promising tho. There are current limiting power supplies. I think Bob Anderson uses one. A dim bulb isn't hard to make. Just a cord with a socket in series on one leg. I made one similar to Shango with the bypass switch.
Def need to get rid of those firecrackers (Bumblebees), but I've brought 'em up with them before. Snip out the "death cap", across the AC line. But, beingstho its been powered up already, hum means open caps. You could jump them and do a slow powerup to see what you have. Again, keep the brightness turned way down in case (likely) you don't have vertical sweep. Sneak it up slowly if you have HV and see what you have.