The bow and stern sections are by far the most difficult parts of the boat to fit and glue in place. The ply is under some serious strain and twist and does not voluntarily want to do what we force it to do. Once we apply the epoxy and glue to the piece backbone, stringers, and bulkheads, we carefully align each piece and work towards the end adding tightly spaced screws.
Personally, I have never been able to get a clamp to stay in place do to the angles involved, so it come down to brute strength and a third and fourth hand to help out. We manually squeeze the ply to the backbone and add the screws about 1.5" apart until it is tight and secured. Then we go around and scrape off the excess epoxy (which is now starting to cure) that has oozed out. Then we take a break and get ready for the next one. The bow sections go on with relative ease when compared to the stern sections.
We also eliminated about 80% of the dreaded Wharram Wobble by extending the lower stringer (when upside down) all the way through bulkheads 4, 5, and 6.