I have had similar problems with warp on my Tiger 60. After covering the wing I found that I had induced different warp than it had bare bones. If twist is your problem then using the heat gun on the covering, and twisting the wing in the opposite direction of the warp you will find the warp will dissapear. Don't overdo it and check as you go. My wing is now warp free, although I haven't checked up on it lately (one year later).

This was advice I got one day from the guys at the field.

Good Luck!!!