This is one of the reasons that, on my PWCs, I glass the inside of the deck and bond it to the hull before glassing outside. It remains flexible enough to work out minor errors. I can also use the deck glass to bond the deck to the hull, no taping outside.

There are some downsides though, Marokse fittings are a problem, and ideally the hatches need to be cut after the outer glassing, etc. Also it is easier, with sheer clamp appropriate PWCs, though not impossible with rounded sheer PWCs.

Et

http://www.etiennemuller.com/northstar/pages/0040.html