Adam, Charlie has a good expanation of the function of the adjustments. I can add a few things in easy terms to understand also.
Since roll centers are measurments to determine the chassis' direction or movement around the suspension as it is used....
The relationship of angle in the upper link and lower arm determines the static roll center. The length of the link determines how much the roll center moves, or migrates up and down(mostly). The location of the pivot points(in or out) determines how much it migrates left and right(mostly). This is how I remember it, it has been a while since I busted out a book on suspension.
So all three things effect roll centers, the difference is how they effect it.
This is where trial and error come in since different people "sometimes" like a different feel, or "think" they feel something different at least.
When in doubt, run what the world or national champion run in their AE set up, I think they have it figured out pretty well, this is probably the reason I haven't opened up my suspension books in a while. LOL
...Jim