I found that my MAK 2 Star easily accommodated a vertically mounted 14 lb Turkey. Used a non-stick vertical poultry roaster in a roaster pan to catch the drippings for gravy. Smoked the turkey for 3 hours at 200ºF using cookinpellets.com Premium Perfect Mix before bumping the pit to 330ºF until the internal temperature at the breast reached 170ºF.
The Money $Shot$ ... Wanted to keep it Low-Carb so I served the smoked turkey ... did I mention that it was superlicious? ... with cauliflower mash and used my wok to fry up some cabbage, celery, asparagus, red onion, and mushrooms.
Gotta love the temperature control that the MAK Pellet Boss provides. The graph below (one of many features of the MAK Grills Mobile) illustrates the lack of temperature swings. The only slight glitches you might see is when I opened the pit to take a few pictures.