To make bed leveling quick and accurate I printed a holder for this very cheap but excellent quality DTI.
Link to the DTI which the bracket fits. https://goo.gl/9HYmRr
The DTI is fitted to the holder and pushed on the the fan housing. The code is selected from the SD card and it will first heat up the bed and nozzle to operating temperature (if required) and then home the bed and pause whilst the height is set with a slip of paper between bed and nozzle.
After a delay the Z axis rises and then descends onto the bed and the DTI is set to zero.
After a pause it then moves to each corner in turn and the bed adjusting screw is turned until the DTI reads zero.
It then returns to to the home position, rises and the DTI can be removed ready to print.
I have printed these leveling knob attachments and they make adjustment very easy, no more fumbling around under the bed.
The gcode is here
I have uploaded another file with the DTI holder further forward to suit other model.
I used 100% infill for strength but I am sure less would work.