I'm attaching the deck to my Outer Island. I'm able to finagle a good fit forward of the cockpit, but having trouble with the after deck. It seems that the hull has shrunk a bit. The deck is fair & flat-I don't want to squeeze it into a "dome" shape. I think I have to find a way to spread the hull wider. I thought of trying to attach an appropriate form to a stick and sliding it down (the way you install a bulkhead), but I've already tacked in the fiberglass tape, and don't want to dislodge it. Suggestions?

Are you planning a hatch for the back deck? Cutting the hole for the hatch gives you a good place to reach inside the boat.
Also, you could consider just tacking the fiberglass tape to the ends of the hull (least accessible areas) and taping the middle of the boat in the 'normal' way, working from the cockpit opening. Again, it helps if any overlap in the tape is accessible for sanding/cleanup via the hatch opening or the cockpit.

Personally, if I needed 'handles' to pull on the hull, I wouldn't hesitate to epoxy a few wood blocks to the outside of the hull and grind 'em off (carefully) later. No problem as long as you have a good thickness of clear (aka fill coats) over the hull glass at those spots...

You are not alone with this little problem....I'm quite careful about putting in 'spacer sticks' as soon as the molds leave the hull, and still have this problem sometimes.