If you are doing a large area, use a roller. Place the fiberglass on a smooth suface pour some resin on it. Roll it with the roller like painting a wall, being sure to get out the bubbles. Brush some resin on the surface you will be applying the fiberglass too, lift the wet glass and apply it. Rolling or dabbing it with the brush.(You will need to buy a roller for fiberglass.)
I've worked with fiberglass cloth and resin and catalyst and all that stuff reparing a surfboard. I'd rather spend the money on glass or any other useable material than work with that mess on such a huge scale.
Ahh yes monkey muck...
You gotta love GG. Acetone will clean that off too.
Mix a hotcoat for the first coat on the plywood. No matting or roving just resin with hardner...after that cures, go to town with the roving and matting...