My wife changed plans so we ate the brisket earlier than initially scheduled. However, I did do 2 8lbs butts right after the brisket. One was foiled when it hit 160 the other not. Naturally, the foiled butt finished much earlier ... I knew it would, but it was way earlier than I expected (took it to 200IT). I double foiled it, 2 towels, and into a cooler it went from 6am until 1pm.
I shredded both butts at 1pm and the one foiled since 6am ended up slightly tastier than it's twin that rested only 2hrs.
Both were excellent, but the foiled and long rest butt tasted better. Not sure which variable made the difference, but I'd like to repeat the experiment :-)
Anyway, I feel much better about doing long rests now.