The default setting for joystick deadzone is 30 I think. I'm not sure yet what a good setting would be for fighters, but have found that setting it a bit lower was good for a couple of old 4-way games. On the other hand, that may have been a false first impression. What I am pretty sure of, though, is that for games that use real analog joysticks (Road Runner, Harrier, Paperboy, the 49-way on Sinistar, etc.)... for those you want the deadzone at zero and configure your mame settings (in the Tab menu in-game) to eliminate the joystick digital input leaving only the analog axes.