Need advice on a big cook

You can do them all at once as you described. Remember that a butt will take approximately 2 hrs/lb, and a brisket about 90 min/lb. Your 14 lb brisket will want to cook for about 21 hours, while your 6 lb butts will only take about 12 hours. If you want them to finish at about the same time, put the butts in later. Remember that you can leave yourself some leeway at the end in case something takes longer to cook by removing the meat when it's done, wrapping in foil and a towel or two, and putting in a cooler.

-John

butt over brisket, plan on the brisket taking alot longer. if there is a big fat cap on the butts cut it off, i cook mine with no fat cap on the butts. more bark and less chance the dripping fat will wash the rub off the brisket. i never cooked a packer with butts, i would wait several hours before the butts went on and plan on resting something in the cooler.these were 8 pound butts and 8 pound flats, butts went 14 hours, flats went 12. temp control was difficult with the meat stacked this high, temp probe placement is difficult with all this meat so watch out for misleading pit temps for the first half of the cook with all that cold meat in there