I am trying to tune an aircraft for flying accurately to airspeed in mission mode. It's ok for altitude control to be compromised to some extent. Increasing the SRATE parameter allows for accurate speed control, however, it introduces oscilations in throttle (often amplitude can be from 0% to cruise throttle%). Reducing cruise throttle % alleviates this to an extent, but it's still not great.
What is the best way to dampen and eliminate (or at least drastically reduce) these throttle oscilations but maintain accurate speed control?