Shew buddy.... you signed yourself up for a long cook. I wanna say 12-13 pounder is gonna be a solid 10 hours so a big 16 sounds like a marathon. I’m in the process as we speak of doing an all night just to make life easier. Personally.... I’d rather cook longer, lower, overnight over cutting it.
that is literally a novice opinion, definitely may not be right lol. Good luck