Http://meatsmokingcalculator.com/ - this should help you figure out cooking times and temps. As for a rub - just salt and pepper will do the trick, then most of us use a finishing sauce of some kind - cider vinegar, ketchup, sugar, a little salt and cayenne... Easy as
With my butts I inject then with apple juice then rub them. I let mine sit for a while if not over night. I also spray mine with apple juice and apple cider vin every time I add wood. I cook mine till a internal temp of 175 then I wrap it with a little butter till it hits 200. Im not using a UDS. hope that helps a little im still very new to this smoking thing.