Use this to make a rod brace of any length and tweakable springiness to prevent unwanted rod motion. Works in the customizer.
They can be made to print quickly for testing, and can be very lightweight while still performing as needed.
Mine just snapped in to place and stay there nicely. The picture is of my upper z-rod.
Example .stl files are for the Anet A8 z-axis rod. I no longer have any play in the rods with these installed.
Make sure you have a good first layer for the tolerance.