In most cases the optimal settings are based on driver preference and conditions. The way I use to test adjustable shocks or different spring rates was to keep making changes until the car started to get harder to drive, or doing things that made me uncomfortable. At that point I would back off the adjustments until it felt better. Sort like adjusting your sterio; you move the bass up to a point that you don't like it then back it off until you do.
Doing a track day is a great way to test out some different settings. You also might want review a suspension tuning chart that shows how shock compression/bump and rebound/bounce changes affect handling. Since the IS tends to push/understeer you would probably be looking at dialing some of that out with the shocks. Don't be afraid to experiment, thats part of the fun of being able to make some suspension adjustments.