I really liked the MCU from printingbuddy but it wasn't adapted to the new Mk4. I remixed his mount to allow it to fit. The top arm attaches via M3 35mm screw, replaces the original M3 25mm on body. The mount simple drops into the base of R2D2 without and modifications needed. Glues in and retains room for the Hex Port (where corner is missing on mount). Each mount has a channel to allow a zip tie to add more security to reduce vibrations/movement of the MCU. 

The arm still uses a M4x6mm heat insert just like printingbuddy's original.

Support needed in mount only in the bottom that goes over the bottom plate of R2D2. Zip tie channels need no support and might need a support blocker added. 

At time of sharing this, you can see I'm still building my Mk4 so this isn't tested in the wild yet, so to speak. If there are any issues, please share.

Remix of mount only included original stand fragment and arm portion only included part of frame adapter. Otherwise built from ground up.