Fixing Hull "Issues"

I think I figured out why the hull expanded:
1. Weather. There were big fluctuations in temperature/humidity when I was ready to glass the hull. I was too intent on Getting It Done, and didn't notice the expansion.
2. Short kayak, lots of small strips, and new-to-me wood. I think that the low-density pawlonia absorbs/desorbs moisture quickly. The ease of heat-bending is a clue.
3. Timing. I'll have to, in the future, find a way to put the halves together while everything is still fair. I may try glassing the hull exterior first in the future.
I went on that Favorite Message Board for suggestions, and as expected, plenty of response. This is one of the suggestions:

Ratchet straps and blocks of wood pulling the hull back into the forms. Fortunately inexpensive, $10/4. Very glad to see that when the gunwale is pulled in, the hull conforms almost perfectly to the shape of the forms.
Of course, now that both sides are glassed, the wood won't react to temperature/humidity changes, but I hope that the whole thing "takes a set" while the epoxy continues to cure for a while.
Nope. 😒 I left the above arrangement in place while I glassed the deck underside. When I removed the forms, the hull sprang right back out to its original shape.
I tried getting the deck to fit by using the straps and blocks of wood, but the hull was very much wider than the deck, and the deck kept diving down into the hull. On to Plan B:

I put the forms back in with the straps holding them in place as in the above photo. I made these sticks of lumber to pull the hull back into the forms. After I got over cringing about drilling holes through the hull, I did several of these. I'm hoping that they will hold the hull in shape enough to be able to work with the straps & blocks.