Actually state of the art for any electro motor would be a frequency inverter, best adjustabillity and much more efficient than only changing voltage (eg esp for controlled fans that run 24/7) did some development on that stuff, but that was in the Megawatt rangeYup a variac would be ideal for this job, scientific variable transformers are best to squeeze the best results out of a pollinator.
yep, i breed my own 8-way landraces hybrids and prefer the most possible variety over uniformity, i've seen a lot of curiositysThese details are going to vary, since trichomes are incredibly different in shape, size and composition depending on how the plant is grown, the variety and epigenetic/environmental factors.
nonetheless i would compare that task to having a lot of springs of the same type but different sizes and alloys - eg categorizing by size will reduce the possible differences, and the calibration range gets smaller...
thanks for the hint to the phd thesis!