It's coming along, calibration still way off but I'm getting there....slowly but surely.

It’s coming along, calibration still way off but I’m getting there…slowly but surely. Definitely need to make some adjustments to my dual head and probe mounts.
http://www.youtube.com/watch?v=FJZXQFu3t30

Nice work! Good to see it printing.
The belt angle between carriage and motor will affect XY movement - it will not be linear to the number of steps. I think it will be slight - barely noticable, probably some math could prove it.
if you calibrate movement in middle it will have more effect on borders of platform in Y-axis.

I get what your saying about the belt, don’t know what I was thinking in the video with moving the mount, that solves nothing. Looks like I am either a: printing a taller pulley or b: sourcing a motor with a longer shaft. In the long run it will probably be the latter. I am really considering dual Z now, I should be able to rotate the Z around 90 degree’s and put it on each side without too much hassle. But first things first…optimizing the head/sensor set up.