It's been a while since I have smoked a shoulder roast. Last time I smoked at 225 degrees and several said that I could get the roast done much quicker if I smoked at a higher temp. Is 225 degrees not the ideal temp for pulled pork?
225° isn't a magic number. I started out doing it that way because everyone else did, but I've moved away from that. On my pellet grill, I do 160° for a couple hours to get some good smoke on it, then bump up to 275° for the remainder of the cook. There is no noticeable difference in the finished product smoked at higher temps. I've gone as high as 300°.
I can't say since each piece of meat is different. Like I said, I have 2 butts just a shade over 6lbs. that I started at 11 AM ish, one has been in the cooler for at least 45 min, and the other isn't done yet. The one I'm still waiting on has lagged about 20° behind the other since I inserted the temp probes about 5 hours into the cook.
What I will say is start sooner than you think you need to. You can hold them for quite some time in a cooler with some towels for insulation. Fortunately, the ones I'm cooking are for tomorrow. I'd rather cook ahead of time and reheat, than not have food ready when it's time to be eating.