I cook LARGE amounts of butts at a time every time I fire up. Usually 20 or so. I quickly trim fatcap and have a large container of injection next to me. I inject quickly and evenly in one pan, and move to a tub that they get the mustard in, then they transfer to a tub that they get rubbed in. Finally, they get piled into a tub for storage overnight in my bbq fridge.
I stake my reputation on every piece of meat I cook. I have had that mentality since I started cooking, and have never had complaints. Why not make every butt like it was a competition (flavor profile aside)? You will never serve a blah or so so product with that attitude...
Just my opinion, and I don't plan on publishing any cookbooks in the near future.
Lang 84" , Bradley Digital 4 Rack , Weber Performer <-- That's Cookin' in STYLE BABY