I used my existing design from this buildplate holder (https://www.thingiverse.com/thing:2820435) and applied it to the MicroCube. This design is using a standard 100mm x 100mm mirror tile (german "Spiegelfliese") as printbed. The tile can be removed and swapped out for another one (for example with a different surface). I used to print on bluetape and recently switched to a BuildTak surface. It works really nice and I like the simplicity of this design.

To print this you need the files Bed_Mount_v2_mount.stl and Bed_Mount_v3_plate.stl. You can also print 4x MicroCube_ThumbWheelM3.stl for the adjustment thumbscrews.

Please see https://www.thingiverse.com/thing:2988574 if you have trouble reaching the limit switch for the z axis with the screw.

The other stl file is only needed if you want to make changes to the SCAD file. I used the original mount, chopped some parts off and attached new ones. The SCAD generates both the mount and the plate, see bottom of the file (comment the part you don't need out).