ElectricGrave. For games that have charge shots, the fix is easy. there is a simple autofire circuit in the Arcade Otaku forums. You make it, (it rapidfire pulses any two buttons by pulsing through their ground, not their active line), put the normal charge shot to button 1, but add in some extra wire (like a "Y" splitter) , to make a copy of button 1, and shift that copy to button 3/4, whatever. That's where you put the autofire.
There is no way to do this with XianXi's cause it happens at the jamma harness, but his is so much cleaner and professional than the one you handbuild on AO. Plus his gives autofire to b1 and b2, of BOTH players.
I will be running both. As I have a 6 board pcb shelf inside my super neo, and 2 of the main games are strikers II and III. The other 4 are Gemini Wing/Raiden II/Raiden DX(already has auto)/ and Viper Phase1 (already has auto)
If I need the charge shots, I will turn XianXi's off, and use the homemade one at the control panel level. I only swap games around like once a month, or so...so readjusting things wont be an issue.
If that concept helps at all, I'm happy to have helped.