I've asked that question about four times now, and the only answer I've received has been from Ahren Johnson, who said I should clamp squares to the 8020 and do my best, and that after it's assembled I'll need to spend some time loosening and tightening until everything runs smoothly. I've done that with my Z axis plate and it's now running smoothly. Part of the trick is to not mount the antibacklash nut until you've got the axis sliding smoothly. Honestly, though, I'm hoping to hear some more advice here in your thread.