I have a question. Does the interlux paint use a catalyst??
Because if it does not.... it's crap.

Spraying Gelcoat. The best way is to use a pro gun that mixes the MEK in the nozzle.

Second best way is to use a dump gun. This is a very simple gun. The gel is mixed in paper quart cups. These snap onto the gun. You simply flip it over and pull the trigger. If the stuff goes off in the gun it's very easy to clean. I've seen this used to spray Imron with nonskid. There are different size nozzles. They cost around a $100.

The third way would be to go to the Depot and buy a cheap gravity feed gun with as large a nozzle as you can get. However if the gel goes off in the gun you can pretty much kiss it good bye!

Prevals work good for small areas.

No matter how well you spray Gel your going to have to sand it to get it smooth so it's easier for someone with less experience to spray.

Gelcoat is safer to work with than paint???

NO! All the stuff is bad to breathe, get in mucous areas,eyes, mouth and on your skin.

If your going to re-gelcoat a boat I would get the 80 grit out on a board file and sand until I saw glass if your concerned about adding weight to the boat.

If your going to paint, use a quality polyurethane or epoxy paint. If you want to have stripes you can put them on after painting and then have them buried with clear so they don't increase drag.

There's a few other things that I don't have time to explain right now. If you like PM me.