I've done our Thanksgiving turkey in my PBC for about the last five years or so. The smallest was around eleven pounds and the largest about sixteen. I have noticed that the size DOES make a difference in cooking time and that it pays to go back and review Noah's video on the subject just to brush up on the fine details.
My results have always been superb and the PBC always comes through as a wonderful bird cooker. I'm counting on it one more time.
I got an e-mail from Pit Barrel advertising a deal on two hangers but given the mass of the birds and the inability to re-stoke the fire in a PBC I'm not going to try it, even with two smaller turkeys. Like some others I'll be watching here to see how a two-turkey cook goes but I'm not going to risk it when I've got a dining room full of people to feed.