Your new trailing edge should work just fine, since, in my opinion, the stock trailing edge on the Four-Star is a bit flimsy, which probably contributes to this airplane's propensity for wing flutter. To take full advantage of the thicker trailing edge, I would make up new, thicker ailerons from very soft balsa to match the thickness of the wing's trailing edge. Alternatively, you could build up new ailerons from 1/16" medium density sheet and ribs, to save weight. It is important to keep ailerons as light as possible to reduce the flutter tendency.