As I type, I'm marinating a 5 lb butt end piece of pork shoulder for pérnil. If it were a whole shoulder with a lot of skin and fat, I wouldn't have any qualms about letting it roast overnight, but I'm not sure I can get away with it with a small piece without it drying out? I want the meat to completely fall apart, but also want it to stay moist. (It does have some skin and a little fat, but my roast is on the lean side for shoulder.) Can I cook this relatively small piece as long as 7-8 hours? At what oven temperature?