1969 Camaro Wheels: Spacers/Adapters Concerns?

Hey guys,

Just getting back on the forum and picking up this project again. About to order new wheels for the car.

My current setup was on the car when I bought it, this consists of 275/35R20 on a 20x10 wheel and 245/30R20 on a 8.5-9" wheel.

My questions: The make of the tire I have no does not appear to rub (fenders are trimmed and something in the inner well looks modified) This tire is 11.38" measured width.

If this tire in a 275/35R20 which is a 27.87" tall tire fits. Is there any reason to think a 295/35/18 which is almost 2" shorter and about the same width would not?

There are the wheels im looking at: https://esrwheels.com/products/sr08 in 18x9.5 and 18x10.5. I would like to run a 265/275 in the front.

If my math is correct I will need about a 1/2-3/4" spacer for the car? Can someone please make sure that with the +15 offset will work?

Thanks again in advance!