Adjust the joystick sensitivity sliders to start low and increase from left to right. This will give you finer control when the stick is near center. You may need different profiles for each axis.
You may have a bit too much dampening, try reducing it a bit.
Dial in enough deadband to eliminate spiking.
Also, keep your plane in trim as much as possible. Use the "auto pilot" modes when you can, and use manual controls when maneuvering. As your speed changes, adjust trim to keep the stick near the center. With the slider settings described above, this will give you fine control in all situations.
popeye