When you glued the doublers did you clamp them and ensure they were flat when you left them to dry? You might also try wetting them with a water/alcohol mix before placing them under a weight. Make sure you give them ample time to dry under that weight.....like a few days. You'll should be able to get that bow out, don't worry. If worse comes to worse you can always go to your local hobby shop and buy the ply to cut out new parts using the old ones as templates. May be a little time consuming, but the great thing about using wood, it can always be fixed. Is this your first build?