I'm sure this could have been much simpler than I made it. I decided to use some of the holes that were already in the rear bulkheads and drill the other holes in the forward bulkheads to allow for a straight shot for the wires.
The only way to drill the holes is to crawl back in the fuselage. BEFORE you attempt it, make sure the back end of the plane is supported. (Don't ask me how I discovered this.)
I put a board down on the ribs and crawled back into the belly of the plane. Then, after drilling a pilot hole, used a step drill to bring it to size. I put the wires in the protective sleeve again.
