I had a similar problem with my deck lid. It's a FB and the contour was off in a different direction. It was high in the center and low in the corners of the front edge. I fixed it by moving the body, not the deck lid. I would think you could slightly bend up the sides of the QP. I know it sounds crazy, but watch this video. Where I had to bend there's actually two panels welded together. If I'm understanding where your contour is off, it'd just be the QP lip that needs to move, so I think a single thickness would move easier.
I put a 2 x 8 across the trunk pans right over the frame rails and pried up with another piece of wood.