I went ahead and drilled holes in the Flippac and installed rivnuts made for composite materials. The ones I used are from McMaster-Carr, part #97217A410. I made an installation tool instead of buying one for $65. The tool is just a steel spacer with a 5/16" hole in it, two greased washers and a 2" 1/4-20 grade 5 bolt. To use, thread the rivnut up to the spacer, insert fully into the hole and slowly tighten with a wrench until very snug. Do not use an impact or you might overtighten and crack the glass.
I taped up the fiberglass, measured and used a new size 'X' drill as recommended. Since you're hand drilling, you could probably go a few thousands smaller:
I recommend testing your installation skills on a scrap piece of material before attempting on your shell:
And here is the finished mount:
With the awning pinned on (the other side of the door hinge is bolted to the extrusion):
Front view, with the new flood lights installed:
All set up:
A couple of notes:
1. I applied some RTV to the rivnuts before installation to make sure they seal. Use only clear RTV - the black stuff will stain your gel coat.
2. After you set the rivnuts, make sure you can thread a bolt onto them by hand. If there is any resistance, STOP. If you crossthread a fastener, you are screwed, as the rivnut will probably spin and get loose, preventing removal of the bad bolt. Chase the threads with a tap if they got distorted during install.
3. The door hinge works great, and I can remove/attach the awning in about 2 minutes by myself. The tab for the off-road lights also works well. Be sure to measure the angle that you want the mounts to sit at before doing your bends. It probably isn't 90 degrees.
4. The rivnuts have a flange that will stick out of the fiberglass. I made a small gasket out of rubber to make it sit snug all the way around.
Arclight