With a set of 17x9's you'd need a minimum of 5.6" of backspace to keep a set of 255/45/17's off the fender. Minimum. Any less than that and it would interfere on the fender side.
I understand now, bummer. I'm sure cragar doesn't offer custom backspacing on those wheels. Those are one of the few sets of 17's that I liked the look of. Back to square one for wheels.