Well I have cooked a turkey as large as 15 lb but never larger.
I would tell you for starters is it get a turkey holder like you would use for an oil fryer and tie the legs and wings back so there are not up on the sides of the chamber or they will burn.
Next, use a rub that's
low in sugar or it will burn and since you gonna be cooking for awhile it's more important then ever!
Now as for lid up or down?? I cook mine lid down for most of the cook then lift near the end and then I turn off unit and let it rest in the chamber lid up to crisp the skin. I lift lid somewhere around 150 to 155
IT in the breast.
if your adding wood chips/pellets then you need to get them going first then set the bird in (setting HIGH) if you want more smoke then turn down to MED or so after you get the wood/pellets going and finish the cook till 165 in the breast and at least 170 to 175 in the dark meat
I always use the two stick method on Turkeys and chickens , I do beer can sometimes as well but only for chickens
