Thanks for clarifying this Clive. Obviously (now that I understand it) you can use the same switches for both limit positions. I see now that it is also what JAZZ writes - just wasn't clear to me.
So, since I am not using slaved motors, I should have 3 limit switches.
So even though JAZZ only uses 3 (+1) switches, it sounds like it is a very nice feature to also have the home switches - or can you also use the limit switches for this purpose? I sounds like it is the same position (0,0) + Z?
I can see the advantage in using the top of the work piece as reference, so that you don't have to measure the difference between a fixed reference point and the work piece surface. How do you do it in practice - do you need a manual rotary control or can you do it from the keyboard (without damaging anything)?