if i use mouse distance horizontal for hipfire, ads ,scope exc do I have to match the fov to the exact value, or match the fov  type, or maybe use multiplier, for the output game and match the fov as close as possible. If thers another way im open for anything i just read that using  Monitor distance horizontal is best for tracking speed which I feel is important for consistency. Thx  

You should try to match the hipfire FOV if possible, the ADS and scopes you usually can't do anything about (with some exceptions).

Make sure the Actual FOV is the same.