The reason supercars are staggered is they are road cars and the roads are shit so if they run a square set up they would tramline like a cnut
(A Macca P1 runs 315s on the rear so the same on the front would be comical) If the road car set up was the best for the car then they would run the same on the GT cars which they dont. Although they still dont run a square setup but more a 'nearly square' one of 300s on the front and 310s on the rear. V8 Supercars run a square set up (280s all round).
You have to accept that on the road 265s all round will be fooking horrible and you could probably gain more from geometry and tyre pressures/compounds that sizes