For the first sizing after FF. Just adjust the fl die where is almost sizes all of the neck (0.005 from a true fl size). Shoot the brass again, you should feel some resistance when closing the bolt after the second firing. Then you can make a final adjustment on how far you want to push the shoulders back with the fl die. This is what I have done I the past. I shoot fclass and can shoot under 1/2 MOA easily.