I am not 100% sure, but I did some math for you that may help.
For 17x& Pegasus wheels with offset 46, the distance from the hub to the outer edge of the wheel is 55.6mm
For a wheel that is 17x7.5 with offset 49, the outer edge is only 46.3mm from the hub. This is ~10mm closer. Pegasus wheels also have very flat spokes which maximize caliper clearance. While 10mm spacers may work, 15mm may be a safer bet. It all depends upon the spoke design.