I am still very happy with my Z routing with the tape measure. I continued it and incorporated both the X runs and tied it along the side. It works but has some kinking going on. I too used the cheap (almost free) 3/4" Harbor Freight tape.
For the Y runs I am struggling with being comfortable with the tape, two sets of wires and braided sleeving feeling secure at the roller plate and not becoming a kinked up mess. Meanwhile, printing some cable chain links to experiment with, again not totally sure how it will secured at the motor/roller assembly.
Agree, 3D printer, MPCNC and boys are the gateway to dad’s doing some extreme tinkering! We did this batman ducted fan Pinewood Derby car last year for the outlaw races. Good times!!