Agree with all you and Neil said except re-installing the little strip at the forward end. Personally, I'd epoxy it from underneath or fasten a small piece of wood under the opening and bond the peice to it. FYI, mine has a small piece of wood bonded on the underside for the bilge plate screw to thread into.
Ditto on just laying in a bunch of gass layers cut pretty much to length. No need to tab significantly to the shoulder of the bilge. I didn't use any fibeglass boards. Just used roving for the bottom layers and then glass cloth for the last 4-5 layers. Dennis C. Touche' 35-1 #83 Mandeville, LA