Easy backlash calibration (experimental)

I have a couple of Dollo3D printers that I've been building and developing for a couple of years. I've used both of the quite a lot for printing mostly functional parts that aren't too tight on tolerances. But recently I started noticing some inconsistencies, especially on circles and started exploring backlash compensation.
Of course to combat backlash, I need to know how much backlash there is so I took a look on thingiverse's backlash related offerings. Tried few but as usual, a design of my own had already started to form on the back of my mind.

Bear in mind this is still a bit of an experiment, I've tested this on only one printer which might have other factors skewing the results.
Results: on the one printer I've tested this on the result's were 0.1 on X and 0.25 on Y, which seems to yield good enough results for that particular machine.

So my backlash measurement involves two models, pro-backlash and anto-backlash. Bot are basic cube, with either added or removed pieces