Papa
Mcnkc is right, but for the large cuts you do need a little bit of a time reference to get in the ball park of when things might be near done. I suggest you read Smokin Okie's "Lessons For New Users" and the 101's for the specific meat you are doing.
Specfic to your question, best to have a temp probe in the smallest piece and one in the largest piece then you know where you will stand. That way, if the small piece gets done you can take it out and leave the larger one in to continue to cook. For your ball park times, calculate for the largest piece to give you an approximate for the longest length of time. But watch the temp on both.
For your first few cooks, until you get the hang of what you are doing, try to keep things simple (K.I.S.S.)
. Pick one piece of meat and cook it. Master that and then move to another.