Looks to me that he handled the situation as well as he could have, given what he had and what he planned to do. He neutralized all of his opponents in a quick and effective fashion.
Unfortunately, it seems as though what he planned to do did not match up with the realities of the situation. Asking for money is not a reason to be shot, thug or not - legally or not. He viewed his "opponents" to be direct and immediate threats to his life, and they were not. They might have become such at a later time, but at the time of the shooting, I don't believe he had justification to do such.
It appears that he gave no warning, took no precautions, and simply opened fire on a group of people (one who was seated while the confrontation took place) with no warning and no life or death justification. Some of his alleged comments after the incident further provide evidence that he was out of line.
Take what lessons you will from this incident, but I wouldn't glorify his name nor put him in the category of purely self defensive shooters.