what i mean is to glass the inside of the deck before fitting them.
1)cut the ply out to the deck shape
2) mark a line around the deck 20mm this is so you don't get resin on this line at this stage so when fitting the decks you get a fresh glue line, no old resin.
3) cut glass cloth to size
4) mix rein and paint onto ply keeping the out side 20mm clean.
5) lay glass cloth on deck and roll through the resin.
6) lay deck on bench with a beam under one side (long side)
7) when the resin starts to go off place a large rubbish bag on top of resin and place a small amount of weight on it to put a slight bend in the timber when cured, to help with deck curve, the plastic bag should not stick to the resin.