1) Number #1 Buck is the ticket.

2) More constriction works better if you want to stretch the range.

3) Absolutely you must pattern your particular gun, choke and load combination for pattern density AND point of impact. Don't rely on one shot for absolute data, shotguns are finicky beast and will surprise you occasionally with a fluke pattern. Good on you for taking the time to investigate this.

Every normal man must be tempted, at times, to spit on his hands, hoist the black flag, and begin slitting throats.