I starts butts (and briskett) around midnight, 225 deg, and head to bed. I check in the AM about 6 or 7 hours later. I have been averaging about 1:15 to 1:30 per lb for cooking time. So if your smoker is analog, get a good instant read. Mine is digital and I still double check with a separate thermometer. Butts have a lot of fat and I have, after trial and error, determined that if the meat probe (on digitals) is not solid in meat but maybe a fat pocket that renders out and leaves the probe tip in a gap, temp readings may be way off, thus a second temp probe. Around 170 degrees you will hit a stall and meat temp will be very slow to rise. It will climb out so check every once in a while. If done before you are ready to serve, double wrap in heavy foil, then a heavy towel and place in cooler till serving time. I do not believe having 2 butts will affect the cooking time appreciably; just monitor both. Good lick!
