Our old Tahiti, when I was early teens, had the old "Bass Boat" heavy metallic flake gel. It was a beautiful 20.5' open bow with a 175hp BlackMax outboard. Anyway, it got a little dull, so we took off all the hardware and had a local paint shop shoot clear on it. It was beautiful for two seasons and then yellowed. The season after that, it started cracking.
Auto clear can't handle the movement of fiberglass. It WILL crack after a few years from all of the expansion/contraction.
All of these tips above are correct. Stick with the stock gel -- or -- get some clear gel and shoot it over the top. It will be a lot more work, but worth it if you plan to keep the boat for several years.