I've only used an old cup sprayer Binks 7 - all metal.
I would suppose that a HVLP would work - that is a good question. With thinning, tip, and pressure adjustment it should work because the Gel coat is reduce to about same as paint for spraying.
Perhaps Jake or somebody else can help that has used a HVLP gun.

I keep on thinking about getting a new gun but I just rebuild my Binks each time. I have a “mini” HVLP for tight spaces and touch up but I not used it for anything but paint. A long time ago when I first started messing with cars a friend of mine who did show corvettes tutored me in shooting lacquer paint and a show car finish. But we all know that paint is only 20% of the job – prep is 80%. He helped me in the technique but always seemed to do better paint job it took me awhile to figure out why – it was all in the gun.
I was using a cheap gun at the time. For Gel Coat you can get away with a cheap gun. I have shot gel coat that came out pretty smooth with the Binks and it did not need to be sanded.

The last few boats I’ve used paint – auto paint on one for a custom job and Alwgrip on the other.

Gel Coat is cheaper the durability falls in between Auto paint and Alwgrip but the effort for Gel Coat is much more then both.

Pepin Cohiba Robustos - mmmmm from Havana?