Layer Calibration  

Layer Calibration

I just upgraded to R3 extruder and so I'm having to re-calibrate my printer.

I'm following the Live Z method from here:
https://shop.prusa3d.com/forum/assembly-and-first-prints-troubleshooting-f62/life-adjust-z-my-way-t2981.html

Here's what I got:

So as you can see, at -1.000, the thickness was anywhere between 0.25mm - 0.27mm, and -1.100 gave a thickness of 0.36 - 0.4mm. Plus, you can see the "waves" that was created.

So I did the second test.

The second time around, -0.975 gave me a smooth surface, but still only 0.25mm - 0.22mm thickness. The -0.950 gave me 0.23mm - 0.21mm thickness, but as you can see, there are holes in the layer (that's why I took a picture with the back-light to show the holes).

From what I understand, when it's perfectly dialed in, the thickness of the square should be 0.2mm, correct? Should I just accept the -0.975 values as a "best of" case and just use that (even though it's not exactly 0.2mm)?

[edit]
I've also seen calibration cubes around. Should I try to print those? What do they calibrate?