4/6 Drop Question

[BalancedBore]

Hey everyone, I am fixing to be doing a 4/6 drop on a 1997 Chevy C1500 4.3. I am planing on going with with American Racing Toque Thrust 20x8 in the front and 20x10 in the rear. What would be the max tire size I could go with that has little to no rubbing for the front and back.