I've seen some EI 3200 shots in Rodinal 1+50, I think, on photo.net, but the grain was quite intense. Pleasing in some situations, no doubt, but not what I'd use for people. I, too, would suggest a developer with better speed-enhancing qualities and relatively low grain. Microphen and DDX come to mind right off the bat.
As for shooting at 800...I think you would be fine shooting TXT at that EI, as well. Once you get out to 1600 it gets to be a tougher decision. TXT @ 1600 is very nice, actually, but it's not for high contrast situations. The already-increased contrast from underexposure compounds the lighting. If, however, you're in a low contrast setting, pushing TXT can add the extra snap for which you are looking.
For a high contrast situations like stage performances with spotlights, where the contrast is quite high, the relatively low contrast of Delta 3200 is very effective at holding the highlights.
And, if you want to go out to 3200 and beyond, it's easier to do so with Delta 3200 than TXT (though I also use the above guidelines - high vs. low contrast scenes - with TXT out to 6400 if I need to).
Jazz show lighting ranges from spotlights to low-power situations, of course. What kind of lighting are you expecting (other than "low")?
allan