I'd also like to add something about D setpoint weighting and transition values. Many of you may not understand what these do, and how they affect your tuning process. Cause they do... and alot... and if you know what to do with them - they are freaking awesome!
So first let's translate the official definitions into something we can all understand. If you want to read what the experts have to say - head over to the betaflight wiki. If you want to read what a hack like me has to say... read on
Second, (and later when more time permits) I will talk about what to do while tuning and as a last step to tuning so that your micro is stable in more situations - and feels more the way you like. This feature changes the ways we identified earlier in the thread for what to look for as we adjust values and how we test out tunes. And if you are scratch tuning like we talked about above on default values - you are under tuning.
So definitions in my own words.
D setpoint weight closer to zero softens the craft's initial response to your stick inputs. Closer to 1 and the fc is gonna push as hard as the pid loop allows to eliminate any error difference between your stick command and where the craft actually is as it begins to respond to your command. This is getting more sharp on initial response to stick commands. Approaching 2 and it's getting razor's edge sharp. I personally like .85 which feels "crisp but smooth".... default is 1.
D Setpoint Transition controls how your craft stops moving at the end of a maneuver. ...but wait ... We've been using D coefficients to tame bounce back at the end of a flip or roll - well that's pretty close to a thing of the past. Default value is .2 and this is an aggressively soft stop to maneuvers hiding bounce back in even the worst of tunes.
So what does this all mean... changing the D coefficient used to be the last step of polishing the feel of a pid tune. Now we can "tune up" the craft to be more stable to external forces like wind and prop wash - and use setpoint weight and transition to "tune down" a more comfortable and butter smooth stick response. If you guys are into this I can rant some more on what I'm doing now that is WAY different than before.