Would I be better off cutting it in half?
Planned on putting it in at around 11pm and cooking though night and next day.
Sounds like you have a whole pork shoulder, the butt and the picnic. Yes you could separate the two, it will make the cook easier to manage, especially if you insist on cooking "low and slow". You will probably also need a meat saw to cut through the bone to separate the two cuts of meat.
Lots of leftovers! Costco sells those two packs too. I use them for parties and pot lucks. If it is just my wife and I we'll smoke them both, keeping one for ourselves and sharing the other with neighbors.