Kim,
It's a bit late now but I would not recommend T-Max films! I invariably shoot TriX (TX400) and develop in xTol 1+1. XTol is great for controlling the highlights when you overexpose/push and does wonders for shadow detail in concert lighting situations. Most of the work in my gallery was in larger venues when I had the luxury of f2/2.8 at 1/60th due to strong stage lighting.
In really low light venues I favour Fuji Neopan 1600 rated around 800 if possible. I have tried Ultrafin SF with this film and got some reasonable results although I would always fall back on XTol as my main developer.
I have tried the superfast films 3200 etc but did not like the tonal quality of the prints.
As for development - be daring based on what you've told me about the lighting situation. Give the film 25-50% more time than recommended. If you have multiple rolls do one at a time and adjust as you go. Digital Truth recommends 7.5 mins for TMax 400 at 1+4. I'd give it about 10 mins. You'll probably get high contrast negs with poor shadow detail but you can tame this to some extent with low grade printing and selective grade 5 burning.
Good luck - it's a lot of fun and immensely satisfying when you get it right! If you have any other questions happy to take a PM.
p.s. John, thanks for the nice feedback - much appreciated.