This forum (Z axis not accurate - #7 by AaronGnade) has a link to the video, as well as a description on how to adjust the settings in Easel’s machine inspector. I don’t know if the settings transfer to other programs, or how to adjust it in other programs, but this’ll at least get you calibrated in Easel. I ended up buying a Shinwa 600mm steel scale off Amazon for $30, it’s marked in 0.5mm increments, and used that to measure out 500 mm for calibration. It took a few rounds of calibration to get it dialed in, but it’s pretty much gnats-■■■ now.