The deck of my next boat will be hand-painted by an artist friend, so it needs a white "primer" for her to start. This will be on top of a layer of fiberglass. Is there a white pigment powder I can add to my fill coats of epoxy to create a white finish? (instead of an actual layer of white primer?

Also, I am thinking of graphite in the mix on the very bottom. I understand that it won't have any practical effect in terms of "slipperiness", but I hear some add it for "hardness" and scratch resistance for rock play. Does it actually help in this regard? What are good sources of graphite powder for this, and how much graphite powder to include in the epoxy fill coats? Thanks.