15x10 fitment on non-tubbed Duster

Now I'm having second thoughts on the backspace limited Keystones.
Was looking at front wheels after focusing on rear wheel specs.

15x7 Keystone's backspace is 3.75" and 15x6 is 3.063". From pouring through the forum it seems that for a Duster a 4"-4.5" is desired. Seems like the tires on wheels with these offsets would be hitting the lip of the fender. The car is already painted and I don't want to roll the fender.

Damn. Wish the Keystones had more than one backspace option per wheel width.