If you're confident in controlling temp in your WSM using the lid thermometer, I'd be tempted to probe each bird, since you've got them on different levels in the cooker.
Not confident with doing that at this point. It registers a range of 50-80 degrees different than the Mav. I went with one probe on the top Main Turkey (Apple Brined) and keep my fingers crossed for the bottom turkey (Cajun Brined).
