I wet out the polyester fleece, off the hull.
One layer is plenty. Lightly sand the area where the skid plate will be applied. You could use saran wrap if you want.
As Greg showed in his pics, mask off the area, that doesn't get the plate ! Apply on top of the glassed hull.
The beauty of the poly, is it's sandable, easy to get (Wally World), and a variety of colors.
I did, like Greg, and mixed graphite, in my epoxy resin, when I skid plated a carbon fiber hull.
Also be sure to use Epoxy resin !
Good luck !