Assuming that the side thrust is correct(no yaw in a vertical climb):
If the left wing panel flies heavy,the model will screw to the left, if you pull inside loops starting from the bottom.
You can confirm that it is a heavy-flying panel,by pushing outside loops,again from the bottom.
The left panel will now be on the right,as you see it from the ground, and the model will now screw right.
If it does indeed do this, add weight to the right wing tip, a bit at a time,until the tracking is satisfactory.
If,doing the above tests, the model screws in the same direction, in inside and outside loops (starting from the bottom), then one,or both, panels have a "flying warp"(whether you can see it or not!), and you may find it best to use an elevator-to- aileron mix to correct things.