You should use the sensitivity from the game you played most (your aim is best). And you should pick the convertion-method depending to how you act in the game.
As the FOV and other stuff changes from game to game most of the time the sensitivity calculation just goes close to your other-games-sensitivity but only perfectly matches it in one point.
So the methods kind of change the point it matches.
360° Distance = if you have to do a 360° to get to your target (not often needed).
Viewspeed v1 is for movements at about 70% and v2 at about 75% of your desktop. (What I mean by the percentage is explained in the video ↓)
And on Monitor Distance you can decide where it should match.
Here is a tutorial on the Monitor Distance:
(Since I am also new to mouse-sensitivity I could be wrong in some things but I hope I explained it accurate enough)