Go to your local hardware store and buy some clear plastic tubing in three different sizes From small to the larger. They also have it in Pet stores that carry fish. They use it as an air hose.
When doing the head of the fly spin your hair around the hooks shank as you did. When you are ready to pull the hair back just stick the a piece of tuding over the hooks eye and pusk the hair back to the rear stopping just short of the tie off point. Now just tie off the hair and remove the tube and you are done. No problem with stray hair and getting them all to the rear using the tubing. This is the best trick I can give anyone when tying bullet heads. Been using this one for many years and it will speed your tying time up by a bunch. The tubing is cheap to. LOL. Just cut a piece about an inch long so you can tie the fly off while it is over the hair. Ron