I get the issue now. HQ-HZ mech brings the reversing switch wire up into the column so that it operates the blinkers and apart from that reverse switch wire (light green in the HX-HZ mech) and the brown wire (in the WB mech) than runs down to the hazard flasher unit the wires are the same. As Goat says leave the WB blinker mech and modify it to suit. Either drill the hole or use a WB pot with the hole in it already.