After trimming the forward 3/4" of one of my fresh air vents per page 29-21, I still have a substantial curve that takes significant force to flatten. I'm concerned that, even with a good adhesive, it might still pry itself free at the forward end. I'm considering clamping it to the top of my workbench while using a hot air gun (Steinel; capable of somewhere north of 800°F) to soften the plastic. Any reason not to try this? Secondly, how much heat should I consider?