RE: 12 gauge slug
I don't feel comfortable using the full choke with a slug. I know I'm probably just a little paranoid, but, most manufacturers don't recommend it. Most recommend improved. That said, one of the best hunters I know, who has used the same browning auto, for decades says "use the full choke, that's what I do". So there probably isn't a big difference, i just don't see why I would use the choke that wasn't recommended when I couldn't be happier with how my slugs are shooting out of my improved cylinder 11-87. I’m comfortable taking a 100 yard shot, if the situation is right.
Paul is right. Shooting the shoulder will damage the meat, but this is a good tactic to use if you in a situation where you don't want the deer to travel far. One example of this is in my favorite stand. In the mornings they are usually headed toward the property boundary. This creates a problem since we don't have permission to hunt the property and there is also a small river to contend with. If the deer is headed that way, I will shoot through the shoulders to stop him right where he is. And it usually works. Another option is the heart/shoulder combo. Quartering towards you, you’d shoot through the shoulder and then the heart. Quartering away, you’d shoot heart and then shoulder on the exit wound.
Good luck.