Glad you've found something that works for you! It's pretty much a matter of what feels right. I have a Defender set up for MacMAME which works pretty well, but I don't know if anyone else could get used to it.
Up = U
Down = J
Reverse = Space
Fire = Keypad 9
Thrust = Keypad 5
Smart Bomb = Keypad 0
Hyperspace = Right Arrow
This ends up putting my hands in about the same positions as on a real machine. Not as good as the real thing, but not bad, either.
So... what's your best score on Battlezone?
