2-Body 1-Head will do very little other than greatly increase the likelihood you’ll be indicted and convicted. No credible SD trainer is teaching this for that very reason. See the threads where we’ve discussed head shots.
Competition greatly improves your accuracy, no doubt and helps to prepare you for multiple targets but it really doesn’t translate over to self defense beyond that.
I’ve been shot, stabbed, run over, blown up and spent the equivalent of several years in very high stress combat situations so I’m a lot like you, when I’m threatened, I just go stone cold and everything goes into slow motion for me.
As a civilian I’ve also been in multuple serious threat situations including one where i had to fire. Fortunately I’ve never had to shoot anyone in a civilian encounter but I have come very close. I hope I never get any closer.
Back to heads, unless you have no other shot or choice put your rounds center mass. Put your hand up against your chest, palm flat with the thumb closed against the rest of the hand. Run hour hand from the base of the neck to the bellybutton.
You put multiple rounds into a bad guy penetrating that zone using even decent self defense JHP’s and you will stop the attacker quickly.
Anytime you shoot for the head it complicates things greatly and prosecutors and juries will be much more inclined to think your intent was to kill rather than simply to stop the threat. From a more practical standpoint the head shot is the low percentage shot if you have a shot at any portion of the torso.
Remember, as self defenders we may only do that which is necessary to stop the threat.