Well I don’t have ailerons, my elevator and rudder servos are in the fuselage under the wing and the covering is already on. The plane looks like a GP PT-40.

My other plane looks like a PT40 also, but has 1 aileron servo under the center of the wing. So should I cut the covering and add weight in the wing? If so what kind of weight should I add?

Yes im checking the balance by using the propshaft but why should I remove the glow plug? The engine is sitting upright