There are two answers here. First, if you decide to install a rub rail, you need a flat surface to fasten it too. So I'd install the deck per CLC specs with an overhang all around. Then I'd glass it. When the epoxy cured I'd trim the deck to fit and install thge rub rails.

If you go without rub rails the usual procedure is to round over the deck/hull joint. This is good because you can't glass it if it's a 90 degree angle; you need some radius for the glass to wrap around. I'd install the deck and trim it to fit. Then round the corners and glass over the edge.

I'd have to think long and hard about glassing the inside of the deck. A lot may depend on what type of failure you are trying to prevent. The cambered deck is, in a sense, prestressed. The inner surface would be loaded in tension if someone were to sit on the deck. The outer surface would be loaded in compression, which is not fiberglass's strongest mode. On the other hand the camber has less effect on fore and aft bending. The boat is already very stiff in that direction from the side panels.

Maybe some of the engineers in the crowd can shed some light on Critical Stresses in the CLC Cambered Deck.