1. no deadzone of thirdy-party controller has no effect on mouse.
2. joystick settings are used when the peripheral plugged into S1 is recognized as a joystick. if it's recognized as a controller or a keyboard or a mouse, there is no use to change these values.
mostly these settings are used for flight sticks and gamepads,
which have complicated axis definitions.
3. generally speaking, MIN speed of mouse should start from 0,
it's easy to understand. but when a game's MIN speed is too slow, you might need to add some to it to gain suitable turning speed and better aiming.
4. just change this value continuously while moving your mouse,
and find a suitable value for your aiming.
personally, i will turn off aim stabilizer in hip, and use 50~90
in ads according to the weapon i'm using.
high values are more suitable for snipers.