I am still trying to understand the reason for the switch. Since the ZW, when the throttle is set at maximum power (10 amps max), produces close to a pure sine wave (see GRJ's inputs above), the more complex wiring seems overkill for the very small benefit of a pure sine wave. No added switch, no cutting off the PH180 plug (I assume), and easier troubleshooting. Use the same circuit on the other throttle for the second loop.
If you are using a Z-1000, which only puts out 6 amps max, I do not think you need to wire the DCS-RC in passive mode, which makes the wiring even simpler. You do need to find a plug for the DCS-RC.
I guess I'm a KISS kind of guy.