the resin is second only to the prep. the prep (gutting, grinding, rounding corners of new wood, filleting) are what gives the resin its ability to work well.
I would probably use poly
make sure you have your PPE
make sure you have a stack of 24 grit discs and sawsall blades
make sure you have a shop vac with a filter bag
make sure you keep going when you hit that point where you want to give up
make sure you have beer on hand
make sure you wash your hands before you pee when working with fiberglass
once you get past the itchy / filthy stage, the resto will pick up momentum.
once you get the stringers installed and tabbed, you will probably want to take a break from the project. resist that urge.
once you get the floor on, foam filled, tabbed and sealed, then its down hill and almost splash time.