Discussion and questions related to the course Practical Motorsport Wiring - Club Level
How you twist a group of wires?
I saw some harness completely twisted.
You do a few at a time. For twisting 2-4 wires, I use safety wire pliers with the other end held in a bench vise.
If you are talking about professsional-level concentric wiring, there is a course on that -- it's complicated enough that it can't just be answered in a forum post: