Thanks for offer to help. I was not able to send a reply to your private note and cannot paste the reply and photos here. The software on this site is not the easiest for me to fathom. Looking at your drawings I think I understand and have ordered a 1204 ball screw with overall length of 500 and a plate to mount the motor lower with a belt drive. This will be at the right hand end. When I get the parts I can work out the details of the mounting and look for a means to mount the left hand handle and scales to make manual adjustments to location, so I have manual and motor control. A Nema 23 motor seems the right size. The other axis may need a smaller 8mm screw for access for the nut, which I will have to machine to fit, but that is after I have tackled the longer axis.
Mike