After seeing your pics I’d say the shelf is fine. It has a good radious and should be fine. However, if you notice the sight window is fairly flat and I think the leather will help. Since the leather will be covered with the felt or whatever the pad is, I usually just use superglue. Be sure to clean the surface of any leftover glue from the pad and I usually rough up the surface ever so slightly with fine sand paper. Just rough the finish, don’t sand thru the finish.