I have a 923 which has true force, but I hear they are very similar.
Here is how my Ghub is set:
Range: 900
Sensitivity: 50
Centering Spring: 100
I have a setting for "Apply settings from game" and that is "On" My hunch is that all these Ghub settings are irrelevant due to that check.
In Game:
Difficulty Settings:
Braking: ABS Off
Steering: Simulation
Traction: Off
Stability: Off
Controls > Wheel > Advanced
Vibration: On
Steering Linearity: 50
Vibration Scale: 10
FFB Scale: 80
Center Spring Scale: 130
Wheel Damper Scale: 200
FFB Understeer: 10
FFB Minimum Force: 70
Steering Sensitivity : 50
I have found that this feels most like a 'sim' type like Dirt or Asetto Corsa, a more "real" type weight to the wheel. Not quite like a real car. It's still kinda loose feeling, but you will get used to it. (it's an arcade game, the FFB and wheel maps are not as good as Motorsport or other SIM games).
Now, as for the "turning on its own" some surfaces you park on will cause your wheels to seemingly turn for no reason. It happens to me, but not all the time always, usually only on dirt or grass or some uneven surfaces. But typically on dirt it will happen, wheel will suddenly want to turn full lock one way or the other. Don't worry about it.
Now, as for it shaking your desk all about - yeah, it does that, they make a lot of noise, have some "play" to them and rattle a bit because they are plastic. I can assure you as someone that has owned Logi wheels for 30 years, this is normal. If it's shaking your desk, then I suggest you invest in a stand.
It's well worth the price, and will help with the shake-rattle-n-roll caused by having it mounted to a desk that also carries everything else.
Good Luck. :)