My Endeavour also has a peaked deck, and I recessed the coaming. My finished cockpit opening is 30.5" long, and 16.5" wide, so about 32x18 to the outside edge of the coaming lip. I had no trouble finding an off-the-shelf spray skirt to fit (Mountain Equipment Co-op). If you can't find one off the shelf, search "custom sprayskirt" in this forum, and you'll find lots of endorsements for Snapdragon.

I'm 6'5", and I can't do a butt-first entry (not even close). With the peaked deck, the recess lowered the front edge of the coaming more than I expected. Although I originally planned to make the cockpit long enough for a butt-first entry, I'm glad it worked out the way it did. I like the fit.