I read the 'how-to' and that should work for virtually all wing sheeting repairs. It's the way I do it too. But I don't quite understand the question. You would not want to mount your servo only in balsa sheeting. The screws would pull out of the balsa too easily. All you need is to epoxy a piece of 1/8 inch ply with a hole in the center onto the balsa sheeting. Mount your servo in the hole and you're ready to go. The wing sheeting will hold on to the plywood and the plywood will hold on to the servo screws.