Grind down 1-2" of the edge of the scoop and the roof using 40-80 grit sandpaper. Place tape along the perimeter of the scoop where resin and fiberglass is not desired. Drill proper size holes for rivets. Mount scoop on roof using rivets. (Can be purchased at any auto store i.e. AutoZone, AdvancedAuto, etc.)
Closeup of edge of scoop. Bonding edge has been grinded down, protective tape placed along edge, and rivets mounted. Once the rivets are in place, grind rivets down slightly in order to smooth them out and facilitate installation. A grinding disk or 40 grit sandpaper can be used for this.
In a container, mix a small portion of resin (around one pint) with 1-2 % hardner (2.5-5cc for every pint). Begin applying small strips of fiberglass matt to the edge of the scoop and roof. Apply the resin to the fiberglass in a generous amount.
Apply a second layer of fiberglass matt to the perimeter of the scoop. 2 - 4 layers are sufficient. Generally you want 4 oz. of matt, so if you are using 1 oz. fiberglass matt you would apply 4 layers, and 2 layers if you use 2 oz. fiberglass matt. Drying time varies for different resins but the best policy is to let it cure overnight. Once the resin cures, smooth it out with 80 - 180 grit sandpaper.
Smooth out the seam using either Bondo, Duraglass, or other body fillers. Body fillers can be purchased at auto supply stores (AutoZone, Walmart, etc.). Sand down the body filler using the following grits in stages: 80 to 180 to 320. The values do not have to be exact, meaning 220 can be used in place of 180. For best result use a sanding block to make sure there are no high or low spots. Follow with primer and paint.
Grind down 1-2" of the edge of the scoop and the roof using 40-80 grit sandpaper. 
