Next I focused attention on the outboard carge ribs and the straps that are called for.
I didn't understand at first why straps were needed. But thanks to my thoughtful brother, Ed, who really studies this stuff I do now. He pointed out that the forward strap is need because you can't rest the rib on the bulkhead flange because that leaves a gap above the skin. You gotta have this outboard rib flush with gap. So you have to cut off the end and make a strap.
I made the strap using paper first to get the shape and coverage I wanted.