Keep track of ride height also. For me this is a simple adjustment and I can feel the difference. Having the long wheelbase and lower front ride height (1-2mm) can really affect the truck. I haven't really evolved enough to tell much difference with the roll centers. I get frustrated sometimes with the washer adjustments cause I don't see/feel much change. Also I sometimes will make a large adjustment just to see how big the effect is. But then go back and start making smaller adjustments.
Like RB said, the truck will grow with you and you will learn it. Practice, practice, practice. That's some of the biggest part of RC.