I can give some advice on shooting distances. As far as defensive shooting and what you should practice at to get all of your important things down like stance, grip, breathing you should probabaly shoot at 7 yards. Persoanlly I shoot almost always at 7-10 yards unless I am practicing to hunt with a handgun. Once you can put an entire magazine worth of ammunition through a 1-2 inch hole in the center of your target without flyers then you should move back. Personally that's what has worked for me and people I have helped teach.