I did not use any permanent fasteners when building my LT18.

Using about 4 cam straps (tiedowns) to snug a section of deck into place, I put several pieces of packing tape (the 2" wide clear stuff) across the deck & well onto the hull. After taping down one section, I "leapfrogged" a cam straps further down on the deck, tightened, taped, then repeated. Had to be sure to stretch the tape to get some good tension. When the epoxy was THOROUGHLY cured, pull off the tape, trim the deck, & voila'! No holes, no nails, no screws.

It might help to trim the deck to approximate size first (leave maybe 1/2" overhang for slop factor). I did not do this, and the excess overhang on the aft deck made it impossible for me to get good pressure on the shear clamps while preventing the deck from bowing up away from the bulkhead. So I ended up with the deck about 3/8" higher than the usual LT18. Oops. Had to fill in the gap between deck & bulkhead with thickened epoxy.

Of course, once I put on all the deck rigging, the clean lines of the deck were a bit spoiled. But I prefer having a fully functional boat rather than a purely pretty one. IMO, deck lines are pretty much mandatory for rescue situations (if not for you, then for the person you're rescuing to grab onto). And bungies are good for those things I can't/won't put in the day hatch - spare paddle, charts, etc.

Val