You might also try ditching the geared head and align using the adjustable feet on your film holder, or better still a larger home made levelling base around the same size as your copy stand base. I’m very wary about extending the camera away from the pillar of your copystand, it is almost bound to increase the risk of vibration even though you are doing everything you can to avoid it. See Vlad’s piece on vibration here (even though he is using a geared head!):
…or indeed @digitizer’s own setup (at least one of them):