I have Holeshot Wheels, like D-50394 appears to have, and their offsets are typically built with 7/8" increments i.e.: 4 7/8", 5 7/8", etc. But they can make some adjustments. Only concern is that they are not street legal, although some do run them on the street anyway.
My Dart Sport has the same wheelwells as a Demon and Duster. My SS springs are moved in 3/4" and I have 10" rims, 4 7/8" offset with Hoosier 9"x30" radial slicks. Section width is about 12.25". The fender lips are heavily rolled and the biggest clearance issue was the front of the wheel opening. Width-wise, I have plenty of room. Moser axles are big bolt pattern with OEM B/E body brakes.