New warning sign,  with 2 options, a  magnet mounted option, and a thin version for cases where a magnet wouldn't work.  

  Again, I printed these without the use of MMU, it is just simply using the PrusaSlicer Color changing inserts, and manually changing the filament.  I have added a picture of PrusaSlicer setup, showing the inserted color changes.  

  The new heights are for the magnetic model has an overall height of 5.6, with color changes of 3.8 & 4.7 mm.

The thin model is overall height of 4.1, with color changes at 2.3 & 3.2 mm heights.  Note, becaus it is thinner, make sure it fully cools before removing from the bed to prevent warpage.

  The size of the model is 120 x 100, but is easily made larger to accommodate your wants, but if you do that, I wouldn't increase the height of the model.  I have pictures of most printed @ 150mm x 120mm width, but a few of the new ones are at the model default sizes.  Note the magnet hole will become larger, but with CA & accelerant, works well anyways.