ABL w/ the Rumba Board

[TechMasterJoe]

I'll be honest... I could do without the ABL and just have an adjustible offset when homing for Z and i would be gloriously happy... because if the glass is level then abl isnt needed and a number to adjust closeness to the bed makes life so much easier than turning a screw

enable Z baby stepping in the firmware and keep software limit min travel false
then under tuning once you start a print you can shift up and down in .01mm steps it's very fine control i just do skirts like 4 times and adjust while it's printing the skirt
keep safe home Z on and keep the Z probe just keep your bed level and disable ABL or just don't call G29 and test it out

I don't have ABL, but like you wish I could auto adjust the initial offset. Could you change this line in Marlin to "1"?

  #defineAUTO_BED_LEVELING_GRID_POINTS2

no it will fail to probe and clear Z i will talk to thinkyhead about adding it