The 9.5’s with 275’s should work, they may need a small spacer. They’ll overhang the rim by about a 1/4” or less, most of the 275’s have a section of 10.9”
or 11” and the 9.5” rims are 10.5” edge to edge. Which would leave you with about a 1/4” of clearance. Which is pretty tight, but that’s about all I’ve got. An 1/8” spacer and you’d be fine for sure, and the center registers on the axles are taller than that still.
The 255’s would be a piece of cake, and being able to rotate the tires is a nice benefit. The 275’s will be tight everywhere, but they do fit most Dusters. Better to have them tight to the springs and adjust with a small spacer if need be than to have them too close to the quarters.
