[vcf-midatlantic] VT320 CRT replacement?

I have a VT320 with a pretty bad case of Being Old. The screen is so dim that even with all the lights off in the basement, it's difficult to read (and if it gets switched to 132-character mode, next to impossible). I know surplus caches of these CRTs pop up every once in a while, and I know other mono CRTs of the same size are often mechanically and electrically compatible, but I'm a bit at sea. Does anyone have pointers for acquiring such things? The current tube is amber, but I really don't care what color it is as long as it's legible. Failing that, how well do rejuvenators really work on these? My understanding is that it's usually a pretty temporary fix at best (like Retr0Brite). - Dave