Not all clicks are clicks
Somewhat adrift from the OP's question, I once had the very bad idea of measuring the movement per click (and between scribed range lines) on issue No. 4 sights.
The brief version is that I started out knowing that these were sights made for military use, most of them manufactured during war where the objective was the rifleman being able to hold Minute Of Bad Guy during a TIC. And of course the reality of backlash in the mechanism, etc. But I didn't realize that the differences through the range of the screw's movement up and down would be so great.
Anyways, watching the measured movement change as I screwed the sight up and down through the range... I finally realized I was about to go down a rabbit hole with no satisfactory ending if I pursued that in search of some consistency or insight.
My Long Branch is normally wearing a Parker Hale vernier rear sight for belly shooting these days anyways, strictly for fun... but that was maddening back then, sorting through the coffee tin of rear sights I had accumulated, looking for a magical one.