Start by following the steps/using the original gcode from jkoether: https://www.printables.com/model/360303-auto-incrementing-first-layer-calibration. Once you have chosen the best live-z setting using his original gcode, then use the 0.01mm increment file in my remix. This will help you further pinpoint the right live-z height.
If you really want to fine-tune further, you can use the 0.005mm increment remix. Any time I get a new steel sheet or do a nozzle swap I use jkoether's model and my two remixes to get a very precise live-z quickly.
The author remixed this model.