Rudder Pedals are hard to optimize because one good setting is unlikely to perform equivalently well on all types of aircrafts. In association with the setting shown below,
I normally will reduce the rudder_effectiveness by 50% of a specific aircraft, of course when necessary, so as to enhance its taxi quality while not sacrificing overall realism.
The parameter is located under the [flight_tuning] section of the aircraft.cfg file.
As shown, there are other flight control parameters one might possibly explore to realize an optimally tuned aircraft.