Given my obsessive, compulsive nature I think I found something. Inside Mastercam X there seems to be a post processor setup wizard. I'll post (no pun intended) more info once I figure out what the heck I'm doing. From what I've seen so far, it asks for things like:
where the center of the axis are (for multi axis machines)
spindle min/max speeds
4th + 5th axis to be defined at mm/sec or degrees/sec
invert individual axis
custom g-code setups for things like coolant; mist, medium, high
...Plus a million other things
I think I found what I was looking for!