Just cooked another prime rib roast and wanted to post cooking info since their is such a wide range of cooking times on this site and in the Cookshack cookbook.
Rib roast, bone in 7 lbs. cooked with 2 oz. of Cherry wood at 250 degrees in a Model 55 on center rack. Took 5 hours to reach 140 degrees. Meat started at 37 degrees.
That equates to 43 min. per pound for medium rare. This isn't the first one I have cooked and I have always had similar results.
Rubbed with rosemary, salt, pepper and garlic just prior to smoking it. Turned out great and I plan on continuing to use Cherry wood for all of my future prime rib roasts.