Using a 5/8 inch rotobraoch tool, a variety of drills, and unibits I began to cutout the hole thru the ribs for the conduit. There is nothing easy about building an airplane except for saying, just drill a hole. Try drilling thru ribs you can't see and can barley feel.
I made a tool to align the holes and it worked okay.
The conduit (from the aviation aisle at lowes, is simply a 5/8 PVC tube.
View thru the accesible ribs.
Easy access here
The conduit disappears into the ribs that are barely accesible.
