Ok, how do you guys do it? I do it on and off. Then end up going back to full length sizing. I set the die to touch the shell holder and then back it off 1/2 turn. Is this the accepted way? Or do you guys get more technical and buy headspace guage and turn it down until you start to barely see the shoulder start moving?

I never really see much improvement in accuracy if any. Biggest thing to help my accuracy was to deprime in a separate stage then move the expander ball all the way up as high as it goes. That stopped neck runout issues somewhat.