If the backlash is known I suppose I can factor it in when I reverse direction just like I have to when using a manual miller and the Vernier's on the handles.

Not sure what to do with the software yet as windows programming is not my thing but have been told VB is dead easy with lots of tutorials. It will likely be a work in progress starting with the mechanical build and a simple stand alone controller I can punch coordinates into followed by talking to it from a PC with a USB/serial converter.

Yes it will be very much man in the loop, it's really pointless trying to over automate, more of a helping hand that saves me being bent over a table for 3 hours. I just built a board with 219 parts on it at an average rate of one per minute. A lot of time was wasted trying to pick up the 0603's that then just stuck to the tweezers. I just bought one of those hand vacuum pickup tools to make it easier but then started getting ideas.