lewjeff,
I did five pork butts for a July 4th party, total weight 27.19lb. I put them on at 8:45pm July 3rd and removed them at 12:15pm July 4th. They were all about equal in siz, figure 5 1/2 or so pounds. 15 1/2 hours for all five, pulled when one on top rack was at 192 one on bottom rack 190. It was a great cook and they were great butts.