Not sure about the "Arcade Power Stick", but I've used the standard 3 and 6 button Sega gamepads without any issues, (only one button works though, the "B" button).
I did try the wire swap mod, and was able to use two fire buttons, but not with the WHDLoad games I tried, (Brutal Sports Football and Total Football), although it
did work with two buttons if I booted those games from the floppy versions...
