Hey Cap, nice looking tin you got there! :thumb:
On the decking, aluminum sheets are expensive and weak which means you have to put in a bunch of floor supports. Then you have to cover it, slippery when wet and hot like a skillet. I reccomend using 1/2" marine ply that has 5 layers and is really strong but it does flex some when walked on.
I use spar to seal my ply rather than resin and once covered I'm not sure how good looking wood will matter. Nautolex is really good flooring and pretty easy to work with unless your trying to wrap corners with it, then it's not so much fun.