[dtvmcdonald]

The problem with the red is that if you have even a teensiet weak CRT, it clips on BOTH high and low sides. The low side clips at the DC restorer and the high side clips
at the CRT grid. Since there are no more good 15GP22s (and if there were, I would outbid you!) the only cure is to reduce the drive to the CRT until the red gun stops
clipping at its grid. This results in a dim picture.

To test this you need an SMPTE color bar pattern that generates saturated
red, magenta, yellow, and white, correctly adjusted for saturation, and a two-input
scope that does subtract of athe two channels. You also have to put the scope probes directly at
the red cathode and grid (both for DC correctness and also seeing if it clips at short transients).

You will likely be disappointed at the picture brightness.

But once done ... the total CRT current will be so low that the HV supply will be happy
as a clam.