Just an idea…
Every time I print something I sit and wait for the extruder to heat up and just before the z-calibration starts I remove the little oozed string of ABS by hand because I don’t want it to curl up and make the nozzle dirty.
Would it be possible to have a controlled, slow retraction near the end of the heat up phase to completely prevent this initial ooze?
I think this would be a great feature! This could also increase the reliability of the z-calibration… since the nozzle stays cleaner in the long run.