After trying to use the piece of acrylic that came with the printer, I noticed what a pain it was. I then saw the awesome leveling blocks from WildBillThe2nd and downloaded them. This is my first 3d printer and I admittedly did read the author's complete instructions. I was puzzled by the little lip at the top. I didn't know where to rest the gantry. I later read his instructions and felt like a bit of a goofball as it was a space for the belt.
Well, I made one as well that was really simple. I wanted to reduce the plastic of it and also added a bit of grippy nubs on the side. In a pinch, they could double as little toy guns for playing with my daughter. Pew, pew!
It is the same height as the acrylic (100mm). Just print two and shove them in and set the height.
Coincidentally, they fit nicely in the tool holder tray that I designed for the CR-10S Pro...
They are just a simplified format.