Epoxy fillet around the outside edge, sand the riser strips smooth on the outside, and then glass the outside of the deck, including the risers.
There is no need to sand the inside smooth until you are ready to glass the inside. It will be much stronger then because of the glass on the outside.
If your steamer will let you bend 1/4 strips around the coaming, then go ahead. I use strips less than 1/8 to make life easier.