I don't have a clue BBJ! I guess you could guess really high in the petition, and if he doesn't counter, then you were either right, or he loses. That might be the easiest way to force his hand. Since I know he is not dumb, if you are going to clean him out, he will have to come clean.
Joint custody can mean a lot of things. If you are going to have the kids more than he does, make sure you get the money you should. I found AZ's child support numbers to be really low, we agreed to a higher number. The judge didn't object to signing off on that!