nancy , I cut the hatches out after attaching and glassing the deck. The only difference though is that I poured a few tablespoons of slightly thickened epoxy down the inside shear seam after the outside gluing (outside)with the syringe was all done and cured. My intention was to have the deck attached enough so that I could finish the deck and shear seam on the outside, cut the hatches out, then have enough room to get closer to glassing the seam tape down as well as wipe up excess epoxy. I think if you try to cut the hatches out when the deck is not attached to the hull you might run the risk of damaging the deck. It's a pretty wobbly piece of skinny plywood construction. The methods used to tape the inside shear look daunting, but honestly not any more than glassing the inside of the hull.