I'll start things off even though I'm not a 'glass expert
If you put gel coat (no wax) down, it won't go off because air is getting to it. I don't know if putting flow coat (with wax) over the top will allow it to dry but it would be a mission to paint onto something wet and I don't see the point anyway.
I take it you're now back to fresh fibreglass on the deck? No bits of ply showing through or anything? I would suggest buying some non slip flow coat ready mixed (without hardener obviously) and just lay that down.
is my build thread but looks like I didn't go into much detail. This in the stuff I used though:
Gelcoats & Topcoats, Non-Slip Topcoats, Non Slip Grey Topcoat, - CFS Fibreglass Supplies
Its not difficult to apply, just spread it and stipple it with a big paint brush, just need to make sure the deck is clean first, no dust, oils etc, give it all a good wipe down with acetone.