The key to good rudder pedal action is smooth sliding parts and strong centering force. The sliding parts need to be some length, to avoid lifting the rear section when braking. Try to make use of (almost) the full potmeter rotation for better accuracy.
It is possible to use proportional toe brakes by converting
the pedal tilt action into potmeter rotation action by means of
gears. Potmeters should then be connected to a hacked PCB from
USB joystick. I havent tried this, as Im quite
satisfied with on/off brake action.
Another version with Force feedback : Rudder pedals with Force Feedback