I went with PVC tubing down the rib holes because the Van's conduit didn't appeal to me. Its also smooth on the inside so running extra wires later is very easy. Used Panduit MHSS-S6-D lightening hole mounts to secure it to every other rib. You can get them at digikey or mouser by the individual piece.
I have the Vans tubing, which is lighter than PVC, and had no issues running wires. You can always push something like 12g wire down through, which I've done many times, then pull whatever you need. If you run PVC, you'll want at least 3/4".
What diameter of pvc tubing did you use?