Doublers can be useful in the right situation, but I try not to use them as they add quite a bit of weight. You can either do as Ken suggested or cut out the damaged spots at a sharp angle and replace. Using a heavily angled cut will eliminate the need for a doubler since there is more surface area to glue to. Yes, it's strong. I did this with my Joker (old pattern aircraft) wing and can still do snaps on downlines, outside loops, figure 'M''s, etc without it breaking. Do yourself a favor and use wood glue.