So the CTC16 CRT only lasted about an hour in opperation (split between 2 days ago and today) before it got so gassy that HV dropped off and the neck lit up like a neon tube.

Story of my life.
This is the 4th gassy picture tube I've had and all 4 of them have the copper evacuation nipple...I think those copper evacuation nipples have a higher failure rate (failing leaky) than glass ones.