Welcome. IMO being that your kinda new to all this I'd recommend cutting it into three equal size chunks and cookin it that way. Not only will it take a lot less time, you'll have more surface area exposed on the meat for rub and smoke and you'll prolly enjoy yourself a lot more since you won't be frazzled from cooking all night and day. Good luck
UDS'-55&16, Akorn, Bar-B-Q Kettle, Drum Grill, miniWSM, cobweb-covered gasser. I'm JD.