I just want to point out that the in-game sens affects both your hipfire and ADS but the FOV only affects your hipfire sens. And also, different gun types have different ADS sensitivities. My tip for getting your settings right in this game would be to:
1) Manipulate your in-game sens until ADS is correct
2) Manipulate your FOV until hipfire is correct
You would have to do this for every gun type though.
For me my Hipfire is about 30cm/360 and ADS for most gun types (AR, SMG, LMG, Shotty, Pistol) is about 50cm/360.