Matt, Anything you do will be temporary. The expansion rate for steel and fiberglass is quite different, so each day, as the car heats up and cools down, it can gradually delaminate.

Using a straight edge, like a yard stick, I would try to roll the edges of the hole inward 1/8th to 3/16th of an inch, tapered out to at least a couple inches or more from the edges of the hole.

Then I would grind your patch, and tape it to the backside of the hole. After that I would do several layers of mat over everything, and after it cures, grind it back to the original contour of the surface.

A good tip is to put a layer of plastic filler over the glass as soon as it has set up. This will cure the surface of the glass, and give excellent adhesion between the two. (They both use a polyester resin.) It will also be a little easier to grind this way.