Thanks for the thoughts Steve. I have limited experience.
I note that SheetCam has a Post option something along the lines of "Mach4 Plasma no Z" or something like that, as well as the "Mach4 Plasma" option.

Generally, would a plasma post be expected to retract between rapids?

Yes, if the part being cut has many cuts or obstacles instead of one long single cut.  Basically, the machine SHOULD operate as per the simulation in sheetcam. 

Steve

Thanks again Steve.
I'll head over to SheetCam and see what I can find out there.

Nicholas.