I'm 1.
I start off with a recommended sensitivity, then I adjust intuitively, if I feel like I'm needing to 90 degree or 180 or even 360, I go higher until they feel comfortable to do (without too many, or any mouse resets), since I aim train on a high sens I don't lose much precision doing that. If I feel like most of my shots are within a confined range, and I'm rarely needing to do 90 degree+ flicks as long as I have good crosshair placement, then I lower and make use of the increased precision, and use downtime to reset my mouse more often.