Why stop at three? Depending on the number of threats, two to the body, two to the head, then two more to the head, then two more... Shoot till the threat is no longer a threat.
Obviously round placement is key. The only way to get good at round placement is practice, practice, practice. No one can tell another what they should shoot because you should shoot what you are good at and what you can afford to practice with and practice with it often.
If I shot .45 better, and could afford to shoot a few thousand rounds of .45, perhaps that is where I would have gone. If is was practical I would probably just carry a 12 gauge shotgun with alternating 00 and slugs, where the shot placement is important and the stopping power is obvious.
Some like Hondas, and some like Peterbuilts. I don't want to be hit by either.







With the Glock 20 you can get a .40 conversion barrel and save a ton by practicing mostly with that...

