Remix of the original spool holder to remove the numbers.  Print a left and a right then add as many middle sections as you need to get the number of spools your MMU can support. The Spool holder coin spacer goes between the middle sections.  There is no need to screw the spacer down.   I am using these with a 9 cart ERCF.  The 5 light blue on the left side of my picture are the originals from the lack enclosure. The other 9 are my remix.

These print best in PLA.

Use the spool hub from the Prusa lack enclosure v2 - MMU2S I remixed this from.  

The rods are aluminum 5/16 x .035 easily sourceable on Amazon.  You will need to cut them to 120mm.