Thanks. I plugged in 125VAC @ 60Hz with a heater of 97 VAC @ 600mA and came up with about 20uF. Note that's with a replacement 6.3 VAC picture tube rather than the original 2.35 VAC one.
Success! I installed the Ametherm thermistor and a 20uF motor run cap. The power up surge current was about 870mA which quickly settled down to slightly under 600mA. That should help extend the life of the tubes and eliminated about 13 watts of waste heat. More importantly the set is still working fine.
I'll pop the plastic screen cover off and see if I can clean it up a bit.
