re: Poker & 25$ NL 6-max: Light 3-bet flops nut straight, slowplay 200bb's deep?
I don't think you have to worry about balancing your range a whole lot, unless you are playing with good players with whom you play ALOT (highly unlikely at nl25). I'm not saying it isn't important at all, but your primary goal in this spot should be to get stacks in, not worrying too much about your image.
I'd probably tank and make it something stupid like $16. min raises tilt the hell out of ppl, and i don't think you have to protect against draws here (if he has the fd he is shoving over you anyways).