I have my thread here:
Remember now-----This is for others too------If you don't inject or probe before the meat is in the smoker for 3 hours at 225˚, you don't have to worry about how big the piece of meat is, or how long it takes to get to 140˚. I would get your smoker to 225˚ or better, put the meat in, and after 3 or 4 hours, put your probe in, and don't worry about what it reads, until it gets to 165˚ (if you're gonna foil it at 165˚).
My gut says based on this, it should be fine. I didn't think about probing temp until ~3.5-4hrs. It was @ 135* then. Thoughts on potential danger??