going to costco to buy a boston butt today, i need a little assistance with it. i never tried it before and need to be walked thru the process. i need to know correct temps, what i spray it with while it cooks and if i should foil it or not. also, i am using a kettle so obviosly temps may be a little higher. i have rubs i just got in from hawgeyes site unless someone has a better idea . thanks