Remixed the original to make it double sided and increase its "roundness". 

The attached 3mf file has the color change set up for Prusa Slicer. A reduced thickness of 2.8mm seemed to make the best tuit.

See Tinkercad model if you'd like to tweak this further. ( https://www.tinkercad.com/things/4YDR9R452WQ )

Have been meaning to try changing colors on a print with my Mini+. Finally got around to it. I'll see myself out.