Need 15" BFG size options for Dads 67 cuda

So you have a reverse rim with a wide section tire and the outside edge of the tire gets close when you turn ? I would think that you don't need to reduce the diameter but need to narrow the tread width. I run 25.5" diameter tires on rally's on a 67 dart with wheel lip mouldings and no problems but they are tucked in more than yours by the looks of your picture.

I always wondered how reverse rims would affect an alignment when they are going by factory specs. I guess the difference in track doesn't affect anything.
Btw are you around the Kitchener area?