Go with the cockpit recess. It looks better and gives more clearance for the paddle and knuckles!

I built a 17 foot Auk and used Nicks book infomation to locate the cockpit. It worked for me. In Robert Morris's book, "Building Skin on Frame Boats", he locates the back rest the length of your foot and the width of your fist, behind the centerline of the boat. Might work on the Auk too. Remember to leave a little space behind the seat back.

Ronnie