Re: 14' Larivee restore
For paint you'd probably want to use finer paper, paint is thinner then gelcoat.
Gelcoat isn't paint so you NEED to spray more mil thickness then you need because you'll cut & buff it more then you would after paint. That removes more material. If you look thru Trooper82 & Decker's threads, they often wanted it just a bit more fair, smooth, needed to remove pin holes or whatever, and cut too deep exposing the resin & glass. It will even show thru gelcoat if the gel is thin enough but not yet completely removed. So then you respray & start the process of cut & buff over again. And repeat as necessary.
I think they both did GREAT work having never done it (Trooper) or it's been a very long time (Decker). But you might ask both to give you a review of their methods, trials & tribulations & whether they'd choose to gel if they could get a do over. YD & Oops both dropped great gel tips all over the place @iboats. They were great resources & their absence is noticed.
If I thought I could successfully spray gel, I probably would try. I am not to that point, but I won't have access to a compressor of sufficient size. When I get to that point, I might roll it on. Either way, I would start my gelcoat work on the hull bottom (as you are) and as it's the hull bottom on a non-show boat, I won't be overly concerned about making it perfect.
I know how well & good it is to plan to let the minor stuff go. I also know myself & the resto process well enough that when it comes down to it, it is extremely difficult to 'let it go', 'it's not that bad', 'it's the BOTTOM of the hull' and not overwork it trying to get it as perfect as I possibly can.
Help ^^^?
