Tires and wheel question.

With all of the measuring I've done, I've decided that a wheel with a 1 1/8" positive offset will center the wheel in the wheel well. I think this would fit a 275/60 15 Radial T/A with about 3/8" clearance on each side, but 3/3" isn't much. The problem is that the cross section on that tire is listed as 11" when measured on an 8" rim & the manufacturer says that every 1/2" increase in wheel width will increase the cross section of the tire by 2mm. With the correct offset, the wheel will always be centered in the well. So if you have a custom width wheel with the correct offset & maybe a 7" or 7 1/2" width, the 275 tire might work. The 265 is probably a safer bet, but neither of these tires is recommended for a 10" rim, so the 10" Centerline still probably isn't going to be the best solution. Probably better off with custom width steelies or something else specially made.
It bugs me that wheel companies all seem to list a back spacing but you have to hunt to get the offset measurement, which I feel is more useful. Centerline also told me that they can make an AUTO DRAG III wheel in a custom offset & the cost is about the same as what Summit sells similar Centerline wheels for. It looks similar to the AUTO DRAG but the center is welded in & the rivets are just for looks.
Mastercraft makes an ANVENGER G/T tire that is also available in a 265/50 15. It's good to know about the Dunlops too. It gives a bit more choice.