This mythical case about the homeowner who was sued is like the hot coffee in the lap. Everyone has heard about it and it makes the rounds, but the reality is the reason everyone talks about it is because it is so rare. The law governing self-defense generally includes the right to use deadly force against someone who is breaking into your home. In general a person has a duty to retreat and not use deadly force IF they can do so safely; HOWEVER, there is usually no duty to retreat in ones own home. As to "how you should shoot them", I will only tell you that you cannot, and should not shoot someone who is incapacitated and no longer a threat; it may or may not be illegal, but it would certainly be immoral.