Southern...the smoke times that you experienced are within normal range for the boston butt. I try to always go for 225F for butts, but I did have to bump up to 235 once when I was short on time (and actually had to finish in the oven).
As a general rule, you should allow at least 1.5 hours/lb, but I always go for 2 hrs/lb to be safe. It is better to finish early and let the butt rest a bit longer than to have to cut the rest period short. The rest time (about 2hrs if possible) is really crucial to allowing the fluid in the butt to redistribute through the meat before pulling, so I would suggest adding an additional 2 hours as well.
As a general rule, you should allow at least 1.5 hours/lb, but I always go for 2 hrs/lb to be safe. It is better to finish early and let the butt rest a bit longer than to have to cut the rest period short. The rest time (about 2hrs if possible) is really crucial to allowing the fluid in the butt to redistribute through the meat before pulling, so I would suggest adding an additional 2 hours as well.