Sorry to resurrect an ancient thread, but it seemed the best place to ask this:
My current joystick mounting bolt pattern is 4 holes in a 66mm x 77mm rectangle. Will some of the holes on the OMNI2 match this bolt pattern?
Yes, there are 4 holes in the OMNI2 which work with these mounting dimensions. BTW, these are the standard dimensions of a "US-type" joystick mount (as opposed to a Japanese-type.)