I've made some changes to get a "cable tunnel" inside the holder.
There are multiple versions as you can see on the images: hole on the left/right/both sides and without holes. Every holder has a tunnel inside.
There is a straight, longer version for top lightning.
I also uploaded the sketchup files, you can modify them if neccessary.
The bar(s) for the led strip can be found here:
CR10 / CR10s Led-Strip Mount V-Rail clippable by Aldidas