I have straightened two wings that were warped with this technique: Clamp the root of the wing to a bench. Twist the wing in the opposite direction of the warp. You will notice wrinkles form on the top and bottom of the wing. Using you heat gun remove the wrinkles. This should straighten out your wing. Be carfull how much you twist you can easily put a warp in the opposite direction you started with - so go easy and use as little heat as you can. Check as you go with your incidence meter. Because I use two I leave them both on the wing throughout the process.

How far out are your ailerons?