Ok you've gotten the obligatory "all day, late dinner" butt out of the way. I guess it's sort of a rite of passage.
But wouldn't it be nice to have dinner on time? And not to have to drag your butt out of bed at 4am? Or stay up all night worrying?
Next time try starting off at 300°. I know, it sounds like a sin. But an average 8-9 butt will be done in 6-7 hours. And contrary to popular wisdom, the finished product is actually better than the all day variety. There is less moisture loss and a nice crisp, mahogany crust. The meat will be incredibly tender and juicy and will have a wonderful smokey flavor. Try for yourself. And no matter what cooking method, the most important part is the rest period. Wrap it in heavy duty foil, then an old towel and plunk it in an empty cooler for at least an hour. It'll stay hot for 4 or 5 hours, so go as long as you want. During this time the meat will gently cool and all that gelatin you've created during the cooking process will settle down and be reabsorbed as the fibers relax.