Do two butts take twice as long to cook as one butt?
Typically, the answer to this question is “no.” If the two butts (or any pieces of meat, for that matter) are not touching each other, then you have two separate pieces of meat that should cook in about the same amount of time that it would take to cook either one by itself. If you stack them or have them pressed together, now you are beginning to create a single larger piece of meat which will take longer to cook than each piece by itself.
