I've had terrible trouble with the Mic6 bed.
I had to mill the bed to get it flat. It was initially almost 2mm convex in the middle.
After milling, I still had issues with warping. I measured 1.5mm concave after flatening with the mill and under heat load.
I did some research and discovered kinemetic beds, where the bed is free to expand/contract during heating/cooling, so I modified the Proforge 3.5 to have a kinematic bed.
Now I need to adjust the home all and home z settings, but I can't find them in the printer.cfg file, so I'm wondering if anyone knows where they are located.
The OEM 20/20 extrusion was offset from center in the front to back direction.