In short you would not need to change your wiring diagram when using the Z4000; simply disconnect TIU barrel jack adapter and connect the wires from the TIU to either the Track 1 or Track 2 ports on the Z4000.
One possible tweak is to eliminate the Variable 1 Input - Fixed 1 Input jumper wires and moving the Variable 1 Output wires to the Fixed 1 Output. Doing so will eliminate the ability to set track voltage through the DCS remote, but the voltage can still be manually set with the corresponding the Z4000 throttle.
-John