[TxDas]

I think this is a more typical scenario for a civilian. When we are told that a head shot is difficult to make during a running gun battle with ranges measured in yards, like in a practical pistol match, it is true for cops and troops who might encounter this situation. But for us civilians, a street confrontation is more likely to be a mugging and the shot may be measured in inches not feet but certainly no more than a very few feet.
In that situation a head shot is not out of the question because the civilian is usually looking at one of two things, either the attackers eyes or his weapon. So you might as well shoot at what you are looking at, as you would during a period of extreme stress.
A LEO, when approaching a threat, will scan the area for other threats, look at the subjects hands and movements, clothes, etc. looking for weapons or contraband and be positioning himself for a possible violent encounter. PLUS, he has been trained to look for the front sight and aim at center of mass while distancing himself from the threat and looking for cover. AND his weapon will be readily available.
For a civilian, I am reminded of the movie, “Body Heat”, where the lover, upon hearing the young daughter enter the house, jumps naked out of the window and stands, momentarily, in front of the girl. When asked to describe the man, the LEO said the young girl seemed to think he was bald, had only one eye and was about 6 inches tall.
What attracts the attention of civilians is not the same as what a LEO will be looking at, we will be staring at the Bad Guys eyes or his great big gun or knife. So a head shot, at 3 feet, is not out of the question, while falling backwards, struggling and screaming. Body shots are made when the shot is taken from inside the pocket or purse because there is no time to get the gun out.
So I say to practice what you are going to do in a real world situation, shoot at his eyes, multiple times. I swing a 2 liter bottle on a string and shoot as it passes and I shoot at floating marshmallows in the rapids.

[Lonesome in Massachussets]

Ambrose Bierce has an interesting account of D-Day, where one American second lieutenant, an Army Ranger, parachuted in before the invasion with (I believe) the 101st AB Division. Anyway, he managed to infiltrate a German battalion HQ area on the night after the landing. The battalion had been ordered to the beachhead the night of June 6. The battalion commander ordered his company commanders to a meeting at battalion HQ. The LT interrupts their meeting ordering them to surrender. They make a break for it. A guard station with an MG30 opens up on him. He dispatches the machine gun nest with two rounds, and then proceeds to kill the fleeing battalion commander, executive officer and all the company commanders with head shots from an M1. The entire battalion is decapitated on the night of the invasion and will not be available to meet it.

Not bad shooting at night and under fire. And, of course, he escaped. The surviving Germans must have thought there was a least a platoon out there.