learn to leave ( the final fitting/gluing of hinging the elevator rudder and ailerons as the very last thing you do before the plane can be called "done". all the covering can be done, the rigging and pushrods can be made close enough during construction for fine adjustment after the final hinging is done. I like to cut the ailerons out of the trailing edge and leave them off (hide them from yourself, if you have to ,....I know the temptation !) until the plane is completely built and covered then hinge them. same with the elevator and rudder. simply leave them both loose...off the plane, no slots cut or anything that would allow them to be mounted before they should be,..... cover everything and then slot and hinge. with out hinge slots in the edges, there is no way you can mount something before it should be mounted and it's not any harder to do with the covering on than it is with the covering off.