What size shafts are you using, and how long are they?

Last year, I was using carbons, and my bow got the best tune possible with 75 grain Muzzy's (I also tried 100 grain Muzzy's). It would be hard to tell what my grouping was since, I shoot at 20 yards and had could only shoot one arrow at one taget at a time. Ruined too many arrow in the past by shooting fixed broadheads at the same target. If I had to guess I would say I could consistantly group them at about 2 inches at 20 yards.