Okay, I tidied up my wiring as best I could — some pictures:
A wiring extension connector and the Z-axis homing switch connector just fit into the lower part of the drag chain bracket — I opened up the drag chain and tucked the motor wires into it rather than coil it:
Then everything can be neatly zip-tied in place.
and the zip tie wire loom idea works well for cable management — I also left the ones in-between cables long in some places, tucking them into drag chains, or zip-tieing at the other end for strain relief:
