With the outside glassed, you'll still be able to flex the hull into position relatively easily. Once the inside is glassed, it gets harder. I made sheer-to-sheer spacer sticks that I put in place in the hull as soon as I had glassed the inside. This kept the dimensions close to those of the forms. I notched the fiberglass ahead of time, used packing tape on the tips of the sticks to keep them from becoming permanent, and used a strip of tape over the spacer to squeeze the hull against the spacer. When I glassed the insided of the deck, I used the same spacers (label them clearly). The photo is of the inside of the deck.

Hope this helps.

Ross