Hey guys!
I almost achieved to set custom FOV values for the first person view! After some research with Cheat Engine, I found the float numbers that actually adjust the first person view. However I'm make them work properly, as it seems the game try to force a base fov, which result in screen flickering between native value and new value.
If there's some Cheat Engine pros, here are the native game float data:
First Person Min Fov: 44.9588623 (float - when the setting is at 0 in the game)
First Person Max Fov: 54.99999619 (float- when the setting is at 10 in the game)
Can't wait to find a way to set custom values!