I will give you my canned answer, when cooking a Turkey on a BBQ the best results will come from following the cooking instructions on the bag the turkey came in for oven cooking. I cook Indirect at 325º-350º. Rub the skin with a compound butter mix and tent if the breast starts getting to brown. Poultry takes on smoke very easy and it is very easy to over-smoke a bird. Another little trick is to place a bag of ice over the breast for about 20 minutes or so, before you put the bird on the smoker remove the ice bags, this will slow down the cooking process of the breasts so the Thighs can get to temp before the breast is over cooked.
Your overnight-er plan may just taste like an ashtray...That would be a long cook for a Turkey.
Either way go easy on the wood chunks. Good Luck and have a great Thanksgiving!