Apparently Vertical Hipfire has no (noticable) acceleration, just as ADS does, and I found ~1.50 to be around 1:1 (not smart enough to be sure or whether it's 360 "Distance" or Pixel Ratio)
I've also previously heard the ADS value is usually a Default of 60% of 360 Distance, so 1.66/1.67 could also be the right value for my testing/conversion
And on top of all this, FOV HEAVILY affects Sensitivity in general. Like an insane amount.