Multiple Boston Butts - Cook Time

If they are touching you may have to increase time.

Unless you have them tied together in a great lump (and why would one want to do that?), your cooking time will vary only a little - and that's the time it takes the egg to recover from the introduction of a larger (relative to just one butt) cool mass.

If they are touching when you start the cook, they won't be for long - in very short order they will shrink away from each other so the cuts touching each other is not a worry.

All that having been said, timing is very variable from one cook to the next and from on butt to the next. I always cook multiple butts (I get pairs in cryovac from CostCo) and have yet to see all the meat in a cook finish at the same time or according to any given schedule - they're done when they're done.

I would recommend you do your best to estimate the time required (1.5 to 2 hours per pound - use your heaviest butt for your computations). If you have to have it done by a particular time, add another hour or two for fudge factor. Then cook to temperature (the meat will be finished somewhere between 195°F and 200°F). If your meat is bone-in, do the bone wiggle test. If it's loosey-goosey, you have your first clue! Then, when a butt is done, remove it from the Egg, wrap in a couple of layers of Al foil, loosely wrap in a large towel (I use an old beach towel), and place in a cooler to rest and wait for dinner (or whatever).