Gday Allan
I dont have access to the camera anymore and it was a QHY8L, so may well have used a different pot.
As to tweaking the pot based on brightness of target etc, i cant see that being critical as if it was, it would have been set out in the pdf.
All they say is set the waveform to 2.2V, which looks like it is merely centring the waveform at that point to set a DC bias of some sort.
Dunno enough about how sensor reading works to comment properly tho
Andrew