I always go with squared. Staggered is only for looks which a spacer can do if you need to. The tire compound itself is 1000000x more important than going from a 275 to a 305. That width makes very little difference in grip. At that point, if you're having traction issues you need a better tire or a radial. Being able to rotate and not spend an extra 100 bucks per rear tires outweighs the looks anyways. The picture above is a 275 in the rear and it's almost perfect, will probably be when springs get installed.