thanks guys! :-)
I'm fairly happy with the state of the design for Y but the Z still needs some more work. Looks like about 150mm from the ball nut that moves the Y to the centre line of the spindle. Using HWIN 15mm rails would drop that to around 130mm, but 20 mm of those numbers are the spindle mounting plate! The Z ball nut is 94mm from the spindle centre. But it's difficult to see with these crayon drawings :rofl: