All the suggestions above seem decent. I'll offer what seems to be working well for me, as I'm in the process now. I did a power wash and a good scrub before all this to remove anything that wasn't really attached.
I've used Pettit brand one part marine top-coat EZ-Poxy Topside. One quart is enough for the whole cap and costs around $60. This is a high quality top coat that is worth the price. Check online, but West Marine is a supplier. There is a Flattener additive available and I'm ordering that for my final coat. To repair any scratches/holes to the cap, use an epoxy and that way it isn't moisture absorbing. Thicker two part epoxy sticks work great and are cheap at the auto parts store. You can dab them before they set up completely to add texture.
Before painting knock down the whole thing with emery clothe (scotchbrite) to maintain the texture, but prep the surface for adhesion. Wipe with microfiber or tack cloth. I used a roller but you can spray as well. One coat - and follow the instructions- it goes on different than paint. Don't go heavy or it will run. After the first coat cures ~24hours, you can scuff the surface again with emery cloth and add a second coat. Below are pictures after the first coat, no flattener.
The color is lighter than advertised so look for a brochure with color swatches.
The last image is water beading on the top. The coverage is good, this top had glass showing the paint was so thin.