I would call one of the big custom wheel manufacturers and find out what they have made for that frame and body - I'm sure most if not all have built wheels for that. That should get you in the ball park.

Each car is different, what works on one may not work perfectly on another if you are trying to go as big as possible on your tires.

Forgeline has a chart to fill in for measurements to help with ordering. I would start by filling in that information and getting their thoughts if you were going with their wheels as an example. Others probably have the same.