What I do is make sure there is NO hinge gap when gluing the alilerons\elevator\rudder to the stabilizers. after that I cover the hinge line with same base covering as the wings or stabs are already coverd with. By doing this there is no way to see the hinge line at all. on my Wideboy I actually coverd the wing and ailerons with one piece of covering (the hinges are on the top of the wing). there covering doesn't interfere with the movment.