"While taking that photo in total darkness, I noticed the 25L6 driving the flyback glowing blue. Should I be concerned?"
To me, the blue glow looks like one would expect from electrons striking the glass of the tube...it is at the internal surface of the glass, right? and not inside the tube structure between the cathode and plate (that, I might take to be an indication of a gassy tube).
Have you tried swapping the caps back one at a time to determine if it is the 100 pf or the 250 pf That is causing the problem?
Incredible job, I would never have attempted to restore a set that is that far gone...Standing ovation from here!
