I do a lot of roll center adjustments on this car, depending on the requirements of the track layout and surface. In general, on lower bite surfaces, I always run the rear at 21mm to get enough roll in the rear. On high bite, 20mm. From that point, using the factory A hubs I can generally raise or lower the r/c one .030 washer and get it where I want it for the right balance of low speed off power grip and on power corner exit traction. This car is incredibly sensitive to rear roll center and it is my go-to setting that sets the stage for the entire rest of the car. After our last track rebuild, it was very loose initially, and I actually went to C hubs and 2 washers to get an even lower roll center than the A hubs and no washers, which is my normal rear RC setup at my home track.

Front R/C is really just the classic exchange of responsiveness and initial steering for easy of driving and is really just driver preference. On tighter indoor tracks, I tend to run the factory R/C almost always (one washer). If it's a more high speed track where decelerating corner entry is huge, then I'll lower my front roll center so the front washes out a bit so it doesn't "hook in" on me suddenly when the car slows down and the chassis levels out. This is just from experience on various track layouts and surface conditions.

Wayne