Found a video about it https://www.youtube.com/watch?v=LE15jh_Nr_A maybe your marlin firmware is to old. You need to set it up in Configuration_adv.h and compile marlin again.
hmmm wont it be dangerous if one side is too high and allows the nozzle to ram into the platform in the midst of checking? may i suggest use a cheap dial? the type with a springy tip, so you have a lot of safe height?
@enhydra thanks for the link, frame just came in today. Got half of it put together already :). Def looks better than my I2. (Still love my I2 though it’s more mechanical looking)