shot-bomb-autofire-change weapon IIRC
for 3 button setup you would need shot-bomb-change weapon and put the autofire on button 4 IMO but i'm not sure if you can do this (when i have some time i can check it....)
or buy a cab or a better supergun... if you have the money for a 800$ PCB you should also have the money for the right tools to play it
