I have been running around 45-50mm rollout with a C2. Thats 1.77 to 1.96 in inches. Ran 45-48 with 3300's on a technical track and now have been experimenting with 47-50 with 3800's on a flowing track.
I THINK it can make a HUGE difference to be even one tooth off from optimum. At least thats been my limited experience as close as I can repeat variables. I've seen what appears to be a 2 tenths of a second difference with a one tooth change. I've posed this question on another thread with no response. For the pro's out there that have done better testing than I - how much difference does one tooth off really make?