Deck underside really doesn't need weave-filling applications of more epoxy as long as you're confident that layer of glass was well-saturated yet didn't float free of the plywood. It just adds weight without adding any structural benefit after all, and it typically shouldn't ge wet either or subjected to abrasion.

I queried Dillon about this when doing my Waterlust, what I'm reiterating is what he told me.

You will want to take some pains to roughen the 'glass+epoxy a little where any bonding to sheerstrakes, frame tops or deck stringers is to happen before you go about bonding it in place, unless you're working so fast that the epoxy's not fully cured when you start the permanent bonding to the hull structure underneath.

So when 'dry-fitting' your deck, mark out on the upper deck's top where those edges are underneath then flip the deck and go about transferring those marks to act as guides where to do the roughing. I used a detail sander but a sanding block'd work just as well.

Thank you for the confirmation of what my instinct was telling me.

Then tomorrow I shall mate the deck to the hull -- I will take your advice and give those mating areas a quick scuff to promote the bonding.

Thanks again -- this is a ton of fun!

Dave.