I can see what you mean about sitting in the sun for too long, but I would hate to see you drill holes in your beautiful gel coat for the mounting hardware.
Have you thought about a large umbrella shade perhaps in the color of your boat so that it matches. You could make a mount inside the boat which would not be visible from the outside, then pull the umbrella shade out when parked. The down side is you would not be able to drive the boat with the shade up, but then again, you can't go very fast when a bimini is up either (I believe 35 mph). The up side is no holes and hardware on your gelcoat.
Just a thought! Good Luck