Hey DjChiena,
I agree with "THE THING" fiberglass is everything when molding something

The body shops use the same stuff when molding.
If you can try to put screws at the bottom of the lip to hold it up. To mold big gaps there is fiberglass tape almost like molding tape but, it is stronger and then you put fiberglass "longstrand" over it let it dry, sand it down until happy, then add fiberglass resin over the course fiberglass longstrand, sand to perfection or until happy, primer. I'm not sure if you are good with molding, it will all depend on how good you sand.
Have fun
DREEM

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