how far does your table travel, "x" & "y" ? go to the next longest scale available. same for the quill. usually the quill is just under 6" the "x" probably should be 24" and the "z" would possibly use a 12".
on my rong fu 30, I used a 6, 12, and 36 but the 36 really could have been 24.
what are you trying to mount these on ?