Quietness ?,who really knows,I get it close to or a little higher than manufactures recommendations,an leave it at that.
Nocking point hight,to low an they wave back at ya',to high an they wave back at ya'.
Set just right an they fly straight.
I shoot split an set my nocking point level to slightly high, by eye.
Never measure it,because that gets you stuck in a preconseaved rut.
By eye and they fly,works for me an has done for over 30 years.
cheers.