Front Tire Size on a Demon?

We did some careful measuring on Saturday and he's decided to go with this 15x 6 wheel that has 3 5/8" back spacing. It is one inch narrower than he's running now (15x7) and has a little less back spacing. We hope that will allow him to run the P215/65R15 (26") that he wants to run.

Thanks for your help everyone.