If you are going to manually turn the appropriate screw to physically adjust the bed, you may be able to use the Topographical map of the grid leveling system. I introduced that almost 3 years ago:
[3dprintboard.com]
Configure your Marlin firmware to use a grid based leveling. Do a G28 followed by a G29 with a T parameter. It will show you the measured heights of the probe points.
Pick the corner that is furthest out of spec. And move it halfway back into spec.
Repeat the process several times. Your errors will get to be less and less. Pretty soon, your bed will be nearly level physically.
BUT.... You will still get better results by letting the firmware do dynamic adjustments during the print.
[3dprintboard.com]
Configure your Marlin firmware to use a grid based leveling. Do a G28 followed by a G29 with a T parameter. It will show you the measured heights of the probe points.
Pick the corner that is furthest out of spec. And move it halfway back into spec.
Repeat the process several times. Your errors will get to be less and less. Pretty soon, your bed will be nearly level physically.
BUT.... You will still get better results by letting the firmware do dynamic adjustments during the print.