[DanEC]

Nice thing about fiberglass is that you can do just about anything with it that you want. But, you’re going to need to figure out the source of why it wants to sit higher on one side than the other or the view from the rear is never going to look right. I suppose most of that is from where the front is resting on the windshield header. I doubt your windshield is off that much ( but might check the angle from side to side). That leaves the possibility the top is twisted/ warped across the top area. I that appears to be the case, it can probably be worked out with heat and strapping down to a temporary support. It will be difficult as applying heat on that large an area is tricky. It might just have to be strapped down to a jig and placed out in the summer sun for a couple months to let it relax. I reshaped a trunk lid by strapping it down to add more bow to it and the played a heat gun back and forth over the surface to relax it and then let it sit a couple of weeks. It’s been fine for 10 years. But too much heat from a heat gun can literally soften fiberglass to a very soft plastic stage - have to be careful.

I’m not saying this is definitely the problem or solution - just my best guess from your pictures.