As on every control loop we should use as much gain as possible. This can be set on a bench run (w/o blades) very well. Run the heli in gov mode and disturb the control with a short full tail input. The system will sepeed up and go back on the target rpm after approximately 1 second. If there is no rpm wag you can use more gain. We should reach 40..60 points, more than 80 won't be needed.