I have, in the past, been able to clip the inductive trigger on the wires leading to COP coil #1. But that was always sketchy and I couldn't get a signal long enough to actually set the timing. So I wired back in the stock coil plug into the COP harness. When I want to set the timing I just pull the COP, and quickly install my spare coil/wires, set the timing, and then re-install the COP.