In the game:
FFB open = 5
Effects on = 4
At the steering wheel:
FFB "Preset" (i.e. levels 1-3) to = 2
FFB Power ( Force ) on = 50%-65%
IMPORTANT!
I have set the rotation to 720, apparently automatic is not OK with some vehicles and leads to understeer, since the rotation seems to be too low and you use too much steering angle... please test it yourself and adjust it according to your own feeling/needs
There are really little effects noticeable, but eg. ACC tells me it's not the steering wheel.
I wouldn't set the power higher, otherwise more effects would disappear... and you risk it overheating and.... needing repairs for a long time ;D