So what would you expect to happen if you dampen too much and too little? In other words, what effect does too little dampening have vs too much?
If you change the outer settings (spring rate) should you re-adjust the inner or are they independent?
The rebound dampening would be how fast the spring is allow to return the forks back to their height?
The outer adjustment make the spring tighter, so it springs back faster and doesn't spring down as far, right?
Too little makes the front end bob.
Too much makes it "pack".
Too much is worse than too little.
If spring rate is changed, the Rebound setting should be checked.
Stiffer springs and/or lighter oil will need more turning in of the screw, but the change needed can be very small.
The opposite also holds true, the degree of change needed, included.
More or less.
It's a bit more complex than just a simple "how fast" though, as one needs a controlled state of motion that still also provides enough compliance throughout the stroke back to the normal point.
So in terms of concept, you had it nailed, but we need to remember the added detail, especially as an insight towards interpreting ride results from setting changes, and what direction(s) to try when doing further adjustments, be those adjustments towards needed improvement or hoped for betterment.
In a word, no.
In terms of 919 forks in the normal range of stroke, as in nowhere near full collapse or full extension in particular, the only thing that happens by screwing that adjuster in or out, is to change the elevation of the front end.
The stored spring energy remains exactly the same, as does the spring rate. (aside from a weeny net theoretical change in the trapped air spring rate by the minor changes in fork extension at the new equilibrium position)
This is why I call them Ride Height Adjusters, although strictly speaking, they are "Internal Spring Preload Adjusters".
On the other hand, sophisticated forks with very long top out springs, actually have their effective their overall spring rate altered by making adjustments to the so called "Preload Adjusters", which are more accurately described as being "top out spring installed height adjusters".