K8200/3Drag ZAxis with one M8 and one M5 mandrels

The problem of the K8200 is, if you resolve a problem, you get focused on another one.
But I like to improve my printer.
My last project is nearly finished, so I started my work on a new Z-axis modification. My problem is, I don't have much money at the moment, so I decided to use M5 mandrels cause I have enough 5mm ball bearings. I hope that I can show you some pictures of the working modification at the end of the week. If there are any good ideas out in the Thingivers, feel free to commen