Brandon, where is your aft bulkhead located? If it's in the standard position forward of the end of the coaming then it looks like an awkward place to have the cut and to have the coaming exposed in transit. Did you put a day hatch back there? Are there total length limitations? This might involve relocating bulkheads but if there's a day hatch then even with your legs there might be room to locate the forward bulkhead aft and include the day compartment in the middle section take apart. It makes sense to glass the faces of the mating bulkheads for transit protection. The potential for assembling grit/sand between the bulkheads makes it a good idea.

For some reason I like the idea of locating the double bulkhead and gluing it into position before cutting the hull,,not that the hull could warp much but it would eliminate a possible screwup. Drill 1/16" holes adjacent to the old bulkhead and put spacer nails between,,damn but there's probably fillet and too much goop to get the second bulkhead next to it,,,hmm that's probably why the Volksyak fellow does it on a newly constructed kayak.
I was thinking if you had 6 1/4" t-nuts anchored into 2" half circle piece of 3/8" ply with bridging tape to the side panels on the interior of the cockpit with similar anchors for the screw heads on the compartment side it would be plenty strong. I'm thinking 1/4" screws with finger turn handles, bolts epoxied into hardwood or some ritzy dingy hardware. Oh,,and all those screws having tethers or some means of attaching them securely to the inside when the hull is disassembled.