I may be looking for something that doesn’t exist, but I’m sure I’ve seen c clips that allow a second outer to be held alongside, while still clipping onto a single size frame clip (not the trek style ones that are essentially two c clips side by side with the middle legs removed and tops fused)

I’m out of style enough to be trying to mount an external dropper and 2×10 to a frame that only has provision for three cable runs, and I’m not a fan of zip ties for this purpose as having cut off the excess I then intermittently find a sharp edge on it whilst washing the bike…

it was hard enough to find normal C clips last time I was doing a build

this might sound daft, but have you thought about filing the sharp edge off the zip ties if it’s a worry?

Cut zip ties with nail cutters right at the Base, no edges