While gun forums are a great place to chat, trade pics, share opinions and pose questions of those more knowledgeable...

I feel that you might benefit from some overall philosophy training! There are many alarming statements in your original post, regarding your overall mindset. (caliber of weapon, shoot to kill, shoot to wound, should I give verbal warning...etc...)

One excellent resource is the book by Masaad Ayoob, In the Gravest Extreme., which deals with self-defense shootings, overall mindset, post-shooting suggestions, etc..
Although written in 1980, it remains relevant to this day.