how big are the two pieces? Small pieces you should use a lower temp, but small to you might be big to me. I'm not in TX so I don't see 15lbers here. I would wrap it too in the last hour to hold moisture in. Small pieces of meat can dry out fast, and you know it is going to shrink. Post how many pounds it is, I think you will get more feedback if we know what you are dealing with. I get 6-8 lb briskets here, but I never went to a butcher shop for a big boy.