OpenSCAD file can be used to very simply change sizes.

Print the clips on their sides.

cableguide.stl is meant to be screwed to the underside of a table or desk and can hold up to 6 thick (power) cables.

cableguide-single.stl can be used either on the underside of a desk or on a vertical plane. This one holds up to 3 thick power cables.

Other variations can easily be created using the parameters at the top of the OpenSCAD file.