After some sanding, foam shaping and other finish work, I started fiberglassing, starting at the seams and working inward. I think at this point it's going well, and I hope to get it finished in one more evening, if it's not too chilly to work the fiberglass.
The foam seems to have worked for the hull-deck gap. I used extra fiberglass on the area to strengthen the seam. Only time will tell whether or not this was a good solution.
I picked up my new Nautolex flooring today and I'm excited to get the fiberglassing finished so I can get it in! I'll have a good bit of sanding to do before I can install the Nautolex, though, and I think for once I'm gonna try and find a cheap Tyvex suit before I do it. I found em online 3 for $10, and I think it's worth it..