Like André, I struggled to visualize the cockpit locker gutters. I thought I'd post a few pictures of my work in progress as they may serve useful to the next person who gets to this point of the build. I'm pretty much done with the starboard side and beginning to nstall the structure on the port side. Three photos are attached that show the starboard side without hinges and the initial steps of constructing the port side gutters. The hatch opens inboard. The end result matches up with Dudley's specs. The initial builder had started constructing the gutters by gluing a supportive strut just inboard of the cowling running from bulkhead B to the transom. I don't think this is part of the design, but I took advantage of it as the strut serves both as a straight support to hang the outboard aspect of the gutter from and as support for the cockpit seating between the cowling and the locker.
Cy Jordan
PS - let me know if the pictures don't come through. I'm struggling to learn how to attach them.