Hi JAZZ - yes absolutely, some way of fitting an end stop is very practical. I also realised that the "overhang", or working distance from the face of the dovetail jig, is only 91mm. So maybe I should extend the Y-axis rails by 50mm or so.
Thanks for the links. If this is the type that hanermo2 uses, I guess that you will need 3 - or maybe the Pendant type is just as good?