The red bleeding is probably the CRT is weak. If it gets better with warm up & looks better with the brite & contrast reduced, CRT is most likely the suspect.
Quick test: Usually there is a low ohm resistor ( typ 1 ohm, 1W +-) in series with
the filament. Jump it out & see if it improves. That will increase the filament
from 6.3 to @ 8V & heat up the cathodes more. There is a very small risk
to this, its a last ditch way to get more life.
73 Zeno
LFOD !