There's the rub, what your district attorney defines as "self-defense." In jurisdictions like California the mere act of going to defend your church will be characterized as "looking for trouble" and your self-defense claim goes down the drain.
More important than the ammunition I buy is the USCCA policy I buy every year:
https://www.usconcealedcarry.com/ Of the dozen concealed carry policies I investigated, USCCA was head and shoulders above the others. USCCA pays your expenses up front. Most other policies will reimburse you, so you have to pony up all your costs before they reimburse you. In AZ your expenses on your first few minutes post-incident will be $30k if you want a worthwhile lawyer. YMMV.
If you have an incident, call the USCCA and 911, let them know you had to defend yourself and then keep your mouth shut and let your lawyer do your talking.