I am working on my Maslow second build - MarkII and here is my take on Z-Axis
First I removed a factory lead screw and plastic fixture - it was wobbly, hard to turn and allows loose movement of router. Thread is 4mm, way to coarse for z axis.
Next I printed three knobs/washers to center T8 x 2 lead screw.
I drilled and taped four M3 threads - be careful when drilling - very small tolerance!
Next I sanded and polished holder and router to minimise friction;
And here is complete assembly
Works like a charm allowing easy removal of router;
I think that the same router is sold in US/Canada under the Ryobi/Rigid name: T8 lead screw with washer is available on the net for example http://bit.ly/2FzCfZK
If you like it I can send you stl files of washers or let mi know how to make it available in our forum.