It looks like your trailing edge stock may have a bow to it. Whenever I see this, I orient the bow forward/aft instead of up/down. A light bow can be straightened once the trailing edge sheeting is glued in place.

What you can do is take off the trailing edge sheeting on the warped wing, straighten the wing and reglue the trailing edge in place. I prefer to have the center of the bow up on the top side (if that makes any sense).

I've straightened a twisted wing by reheating the covering but not a warped wing.

Best of luck,

Joe