Set the fov to 70 * 1.46161 as that is the fov that the game is running at. The ingame value is irrelevant.
Holo = All 1x scopes, and ironsights for pistols (not RE-45), smgs and shotguns.
ADS = ironsights for lmg, ar, snipers
2x, 3x, 4x, 8x is not in the calculator, and 6x and 10x is the kraber.