I designed the z axis mount and used mala04's source file for the propagating guides.
There is no need for the 4x M3 bolts and nuts.
The 2x M4 on the top do not stand proud and there is no contact with the x-axis belt. The horizontal M4 bolt must be tightened in place before you pass the lead-screw threw.
Edit: Had to redesigned it, there was a misalignment problem with the vertical M4 bolt hole. Now it fits perfectly.