Sorry, but I should have made clear that my autopilot design experience relates to fixed wing aircraft so I won't be able to help with rotary airframes.
I should also emphasise that the databse I have relates to PID control only. After a lot of hard work, I have established which stability derivatives the PID gains depend on so that the job for the user becomes one of estimating certain stability derivatives (for which formulae are also available). The PID gains then drop out as functions of speed. Robustness is assessed by perturbing the values of the stability derivatives.
Finally, could I caution people using textbook PID tuning merthods to do so with care. They concentrate on obtaining a good response to the desired input. In a flight control context, it is just as important to be able to reject unwanted disturbances and this modifies tuning objectives.