Dry rubbing tonight is fine, you do not mention the size of the butt, nor the temp at which you will smoke it. I will give you my opinion and you can take it for what it is worth. Firstly the butt is one of the most forgiving pieces of meat you can smoke. Let's assume a typical butt of say 10 pounds. I would start that butt at 11 AM at 235 degrees. It is important to monitor both the internal temp of the butt as well as the temp inside your smoker. I always foil my butts at 165 then take them to 203-205. I pull them and place them in an ice chest wrapped with a towel for at least an hour, however two or three hours will not hurt, before pulling. I enjoy hickory wood the best with my butts but this is purely personal taste. I caution you to watch your temps closely and do not worry if it gets done at 6 or 7 just put it in the ice chest.