Hi Drac, I just noticed your Z problem. OK, here's how you can determine wether its the ball nut, or the ball nut mount bending. Lock your Z-axis, turn the z screw by hand, if you get backlash then it's the ball nut since you are not using any torque just hand pressure and you have already eliminated the possibility of your end bearing having any slop, make sure your z-motor is unplugged. If you do not get backlash by hand then you move onto your z-axis ball nut mount. If you think that is it then double check your dimensions of course you know that already. You can also remove the alignment pins if you used them and drill and tap those holes too in your z block, that will give you the main center bolt and 2 extra bolts for holding it solid. Actually I don't even know if on your machine you have the 2 extra alignment pins. I'm sure a lot of us would like to be there to help you out but we can't, so just throwing thoughts out there. Hope you find it.