I've been trying in the past to align the head of floppy drives by adjusting by small increments the optical sensor. Sometimes I was able to do the job, but it was is long a boring process because everytime you have to eject the disk, adjust the position of the sensor and re insert the disk.
I am wondering if it was possible by mean of an ad-hoc software to constantly seek for track 0, so during these attempts I can adjust the the optical sensors until the floppy is able to read to read it, this would avoid the countless numbers of disk ejects.
But I don't know if it is possible to control the floppy drive in this way though the SWIM, maybe the initial seek of track 0 is implemented in the floppy drive itself and cannot be bypassed.
During the factory process they should have had some dedicated procedure, maybe a special floppy disk with only track 0 and an oscilloscope to read the flux. Ok, just wondering...