I dont think they have a torch height control option as of yet or add on, so that might mean its not the right thing.

the usbcnc controller has its own control software, as opposed to mach 3 which uses the parrell port to send the pulse signals and deal with all the inputs and outputs, which is why a BOB is required.

I'd recommend contacting Gary at zapp and telling him what your trying to achieve and see what he suggests!

Andrew