what, precisely, do I see when I am looking for "stylus deflection"?First, note that I said "cantilever deflection." If you are viewing the cartridge from the front, and if the anti-skating force is significantly misadjusted, as the stylus enters the groove of a rotating record you will see the cantilever deflect either to the left or to the right. In other words, it will change its angle relative to the cartridge body, either towards the spindle or towards the outer edge of the record, compared to its position before the stylus made contact with the record.
If you are unsure as to whether or not you may be seeing a small deflection, it might be helpful to misadjust the anti-skating until you definitely do perceive a small deflection, and note the corresponding setting of the anti-skating scale. Then misadjust until you see the same amount of deflection in the opposite direction, note the setting, and set the adjustment mid-way between those two points.
Regards,
-- Al