Noaileron differential used. BALANCE is critical for super knife edge. Mine is 4-7/8 back from leading edge. "the 2 screws that hold the carb to the rest of the engine came loose. when i tried to tighten them, i accidentally stripped the holes in the carb" I have 4 Magnums, every one has had this same problem. Just goes with Magnums. Just be patient, wait for a day when there is not much wind, get it set up right and you will fall in love with this plane. You did not say anything about prop? APC 12.25x3.75 will make the plane fly like it's on rails! Be sure an check lateral blance too.