I had a warped wing that was much worse. I went to a pal of mine and he wet the wing with a mixture of water and ammonia then secured it to a table and shimmed the warpes in the oppisite direction just a little past where you want it. Waited a few days and the wing was perfect. It has stayed that way for a couple of months now. I didnt believe it could be done. It was a completed d-tube structure. Hope this helps
Good luck
Brian