First of all, don't change the FOV Type, leave it on Vdeg, because in the game you set the FOV with the vertical measurment. You can actually see the Config FOV, which 45, and you can't set 45 FOV in the game, so leave it on Vdeg. In Rainbow Six: Siege, when you change the FOV or Aspect Ratio your 360° distance does not change, your sensitivity is going to be the same no matter how you change it. Yes, it does feel faster. I saw a video about this which I can't find but in that video the dude explained that the actual sensitivity doesn't change when you alter the FOV or Aspect Ratio.