mc.mcAxisSetPos is work position
mc.mcAxisSetMachinePos is machine position you would start with this one for the first spots so it a home position, then use the first one for the magic eye when it see the gap or what ever reset`s to x work zero
if the wire is in a long run you wont need to home each time just once then work zero what axis`s need to be zeroed then run the bends then when magic eye see`s the gap reset to work zero start again.
if it`s a sort run and you change wire homing is a good idea each run
you can use mcAxisSetMachinePos (mInst, 0, 0.0 /* set part zero */);
you can do this in lua or a macro b for you to get help you need to make a start on the code unless one of the mach boys helps you and have a look in the M4 api you can get to it through the Lua editor