Sorry, no pics, but the notch is pretty much exactly the same size as the bundle of wires. You cut the notch to about the right size, fit the bar, if it's not big enough cut a little more, and repeat until it's the right size.
I think if you try to cut based on a picture of a notch that somebody else made, you very well may end up making it too big leaving room for the wire harness to move around causing the edge of the notch to cut into the wires and shorting them out.