I agree, forget the synchronizer. Just make sure the engines are running properly. Do them one at a time with a final test of holding the plane with the nose pointing up to the sky. Make sure the engine does not slow down and stays constant. Shut it off and do the same with the other one. Refuel and go fly. I have no idea why people try to sync their engines. It is something that will happen if both engines are running properly most of the time. Do not try to force it or you could end up with an engine out or a lousy running engine.