The .53 really doesn't need much for break-in. All I did with both my 53 and 46 is add fuel, run a half tank on the ground to make sure it'll hold a slightly rich needle setting then refuel and fly. Personally the smallest prop I'd go with the .53 is an 11x5. Mine turns a 12x4 wideblade prop at 13.2k set for flying, on 5% Omega.