You are really cutting it close on being able to get rubs or more importantly......PRACTICE.
Unless you are Allen Iverson and don't need practice. :)
I'd use a butt vs shoulder.....much easier to prep and cook (for me, at least).
My favorite butt rub is Bad Byron's Butt Rub & my favorite brisket rub is OakRidge Black Ops. The good news is that both can be cooked at the same session. I'd try to target 250 degrees as a safe temp to keep the grill. Not sure how many you are cooking for....or the capacity of that smoker.
Probably only have room for an 8-9 lb butt and a 6-7 lb brisket flat. Allow around 2 hrs per pound (not total meat weight, but of your largest cut) plus an hour of initially grill set up & stability run time.
Start the day before and be willing to loose sleep to watch this cook carefully.
I'd wrap the brisket in foil after ~4 hours. It'll make it more juicy.
Start probing them when their internal temps get up over 194 or so. When they each probe tender all over.....take them off and wrap them tightly.
The pork pulls apart much easier after resting an hour. The brisket slices better after at least that much time.
Getting done too early is much better than being late and stressed out with hungry and disappointed guests. You can always put it in the fridge and reheat later in the oven.
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