wheel deal
Thats why I wrote concerning wheel width, wasnt sure just how narrow they are, knowing a tire with about 7 inches across the carcass is about as wide a tire as you can put in the well, and to prevent rubbing with that, running a 7 inch wide tire with a 7 inch wide rim would require a 3 12/ inch offset, to center the tire and rim in the wheel well. Wasnt aware a 25 inch tall tire would be too tall as well.
A 25 inch tall tire in a 15 would be a 235-245 X 60.
OOPs!
235-245 are about 26- 27 inch tall. Probably the ideal tire would be a 225-60 X 15.
I would run the 225's on a 6 inch wide rim. with a centered center section, meaning a 3 inch offset.
The alternative is to tub the rear and radius the wheel wells.