Theboxotruth don't lie :no:There are a number of articles on this. You need information, not opinions. Here are a couple of good places to start:
The Box O' Truth #3 - The Shotgun Meets the Box O' Truth - Page 1
Brass Fetcher Ballistic Testing
O or #1 seems about right to me.I use #1 buck for what I feel is the best compromise between stopping power and reduced overpenetration. 00 buck, to me, is too likely to kill a family member or pet in the next room, or maybe even a neighbor. #1 buck reduces that chance somewhat while giving up almost nothing in stopping power. It is somewhat hard to find though, so I usually have to order it in bulk.