Shooting to wound is illegal if you are a CCW holder. If you are justified in shooting then you shoot to kill because you fear for your life. Shooting to wound implies you had no fear of your life, therefore you had no right to shoot. Shooting to wound only happens in old 1940s western movies.
From Zimmerman’s lawyer, I think we can say that Zimmerman wishes to God he had only wounded Trayvon.
In the case you describe, when a civilian is dealing with an intruder or with somebody threatening your life or the life of another, you shot to stop. Usually this means you shot at the center of mass or torso. An element of proof that you shot to stop, rather than to kill, is, having stopped the other person, did you continue to shoot into him or did you take any steps such as immediately calling 9-1-1 to bring in medical attention.
You use the word “fear.” Just to be sure, the standard is reasonable belief that your life or the life of another is imperiled. This could be what you mean in your use of the word fear. If you’re reacting emotionally, you’re risking a manslaughter.
Here’s some good advice regarding the use of a concealed weapon:
http://licgweb.doacs.state.fl.us/weapons/self_defense.html
Again, from what I can tell, the legal authorities have been conducting themselves correctly in this matter.