Lots of different ways to do things. Maybe no one is better than the other. I reviewed your reference and see that his methods are similar to yours. When I did mine, we followed a different route.
First we built the stem and transom and then joined them together with the keelson. The stem and keel were purposely lined up on a flat surface to ensure that the hull would be straight and not hogged. Thus the keel was built at an angle rather than horizontal as you show. What this did was ensure that the top of the deck was perfectly straight and there could be no twist to the hull..
Once the hull configuration was stable the frames were slid in underneath the keelson. Each was notched appropriately to fit in tight. The top of each was also on the same plane as the stem and transom.
We used marine plywood, which is made with a good waterproof glue. The biggest issue we had was the final bend to fasten the material to the stem and bow sheer. Naturally we started from the stern and screwed every 4" as we moved toward the bow.
This was not only a family affair, but the neighbors were into it as well. I had a half dozen neighbor ladies operating their stoves and bringing over kettles of boiling water as fast as they could. Each kettle poured onto the plywood allowed us to bend the wood (inch by inch) and attached a few more screws. The sides were not too bad, but the last 3 feet of the bottom was quite an event.
Sadly, all we had back then were brownie cameras so I didn't get good documentary photos.
Keep your info coming. This is turning out to be the best thread of the year...
PS - if you haven't already, google Clark Craft and Glen-L. Both are in the boat building business and they sell parts and materials.