I built my 60120 using the supplied 75x25mm & 50x25mm drag chains. I have a total of 12 cables running in my main drag chain (4 x 6mm encoder cables, 4 x 10mm servo power cables, 3 x 6mm proximity sensor cables z, x+, x-, 1 x 15mm VFD flex cable).
It's pretty crowded in there !
Looking at the more expensive and industrial drag chain solutions ( I got quoted US$600 for a 150x30mm chain!) you can have 2 layers of cabling, segment the wiring so it doesn't tangle up and cross over.
Wondering if 3D printing the following inserts, or cutting them out of a foam material is an effective way to avoid problems of cable wear, binding cables etc ?