This is a simple tweak to the awesome spacers made by Lollofenix. I just split the file into 3, oriented them for printing, and gave them some English names.

I recommend printing on 0.1mm layer height, and if you are using Cura you should set Top Layers to 9999. This is better than a 100% infill because it causes all layers of the print to be printed with the care and fill rate of a top layer, which are designed to be full and flat.

If the 2mm spacer isn't enough, you need a new spring. Metal springs wear out over time, and eventually you need new ones.