Instead of no scaling, which is what you'll have unless you enabled scaleing in advanced. Or default scaling, which is a straight stairstep low left to high right.
Try like the picture above, using a low curve. This "should" get you more fine control in the center but full control farther out. More so for pitch than Roll.
If your flying with the twisty stick the only thing I'd do with the rudder is increase deadband. So you have to twist a bit farther to activate it.