Customizable cable organizer for shelves

I had a mess of cables running from the computer to power plugs and devices, all laying on the desk, so I decided to do something about it...
I designed this cable organizer that fits on the shelf I have just over my screen and have the cables to go throught it and hang away from the desk...
The shelf is mounted on three rods that are fixed to the wall, so I can slide it out a bit, insert the part, and slide it back in place. No drilling...
Consider a couple of extra mm when inserting shelf t