I'm new to the hobby and have picked a Sig LT-40 to build as my first kit. I'm having what I think is a bit of a problem. I've done alot of reading before deciding to start building and I know the importance of keeping it completely flat and level. I got a 24" x 80" hollow core door as my building surface and have a celing tile on top of it. It ran my large T-square over it and it is indeed flat. My problem is both my balsa rear spars and TE's are a bit warped. I've read somewhere about moistening them with Windex and weighting them down until they dry to try to flatten them out. Is this an acceptable fix? I've read alot about how Sig has high quality kits but I"m a bit disappointed thus far. (I got my kit from Tower Hobbies).

Thanks.