It may be too late now if you have lowered the sides, but surely there would be a simpler way to deal with the outside edges of the deck.

Instead of having the edges curve down to meet the deck, why not just have them continue fairly straight and meet the hull at a sharp angle? If you do that, the best way to join may be with a sheerclamp rather than tape on the inside.

I have joined the back half of a couple of K1s that way.