I'm new to SheetCam but am slowly getting the hang of it.

I've built a CNC plasma cutter with a floating head. (torch is free to move up and down on a linear slide) I have a proximity switch that triggers about an inch after the torch head meets the material.

I want the Z to move down till it senses the material and then tell Mach to pull up (about an inch in my case) to set the torch to the proper piercing height.* I have a floating head that moves up and down and a proximity sensor that is triggered after about an inch after the torch hits the material pushing it up triggering the probe signal.*
(I hope this makes sense)
What will I need to do to instruct the machine to probe the material then pull up a certain distance (again, about an inch) so the torch is in position to fire and pierce?
I have SheetCam and am learning it. Any suggestion as to what post processor to use with Mach 3 and the CNC4PC THC-1?