What kind of cut is it? 5 lbs is small for a true Boston butt. You may actually have a picnic cut (which is the lower part of the shoulder, down the leg). Anything under 7 lbs will be unpredictable on timing. Just to be safe, I would allow as much as 2.5-3 hours/lb. When it hits 190, double-wrap in heavy-duty foil, place a towel in an empty cooler, then the butt, then another towel on top. Let it rest at least an hour. Pull, and enjoy!