Topcoat raw fiberglass for SeaDek

I talked to FGCI today. The product sounds inticing. I asked if I should resin coat the deck first. He said to just sand the deck then paint on their brushable product. He said it needs to be thick, at least a credit card thick and levels well as long as you do not overwork it. He said to brush on thick and not to brush back and forth. I'm not sure he has really seen how rough some of the decks can be though, Once the glue is gone I will inspect mine and decide. I'm still wondering if adding a thick coat of resin would help get closer to smoothness.

For others who have done this project, How much gelcoat do you think I need for a 96 Sport? FGCI's white gallon is $88. Their 5 gallon bucket is only $287 which lowers the per gallon cost to only $57. I'm thinking 3 gallons might be enough but at the price break, I should probably just order the 5 gallon. I plan on painting seat bases and bottom of engine cover too.

fgci (fiberglass coatings inc) has a brushable gelcoat product, i used it and it self levels pretty good even on vertical. But lack of doing a test panel first, and not using a mil gauge caused me to get a cup gun, regular gel and lots of sanding.
Practice may make the brushable less labor intensive but id bet there is a significant amount of grinding to prep the glass after the carpet is removed.

As part of the current restoration of my 96 Sport, I am going to pull all of the carpet, replace ski locker hatch, square up the seams and coat the raw fiberglass.

In a similar restoration on PN, someone used Monstaliner with decent results. The only issue I have with the Monstaliner is that it has a heavy orange peel texture. This is fine on the floor areas mostly covered by the SeaDek, but I don't love the look on the exposed areas like seat bases and lower part of doghouse.

Has anyone come up with anything better in the last few years....most of posts I've read are a few years old now. Or is good old fashioned gelcoat the way to go? I liked the idea of the Monstaliner because you can brush it and it is somewhat self leveling.

Thoughts?