AAR/Stinger Fender Fitment Issue

I haven't had that exact issue but I have had fiberglass panels that didn't fit well. Had some that were way off!! I carefully pulled the panel into place a little at a time using clamps. I didn't pull the panel all the way into place (it might crack), just enough to heat the panel with a heat gun to make it relax. Once the clamps get loose you know that the panel has relaxed then you tighen the clamps a little more and re-heat. Just don't put too much heat in one place and use your hands to see how hot the panel is getting and to make sure that you're heating it evenly.