Spacers are a big help in keeping the shape while continuing to work. I use them all the way up to glassing the hull and deck together. 1" near the center line of the boat will be no problem, but if you have that much at the bow and stern it's going to be a lot harder to move. One trick I used comes from fitting steel plate together for welding and works quite well for this application. The link explains what to do. I never have needed to use epoxy to glue the fittings on, hot glue has always worked for me.

Kent