Alright, I've read ALL 11 pages of this and here's my take.
I have done 1 and ONLY 1 smoke in my #3 so far and it was a tiny little 6.5 butt that I gave to friends. I brined it using DM's recipe on the first page, minus the instacure. It was very moist, loved it!
Here's where I differ from the rest of you. I have always smoked butts and briskets fat side down. The reason is two fold. The first being that both cuts are loaded with fat so no need to put fat on top to "baste" the meat as it cooks. It simply isn't needed. This also will make your rub "wash" off during the cook. Case in point, look at this picture I took of smoking a butt and a brisket on the Keg. The butt on top rendered down to the brisket and "washed" off the rub/bark from the top of the brisket.
The second reason I do fat cap down is a built in heat shield from the heat that is radiating upwards. Being that electric smokers do not have a true diffuser, this becomes even more critical.
I don't claim to be a know it all about electric smokers as this is the first one I've ever owned/used and I've literally only cooked on it once. What I
do know is how to cook and have cooked God only knows how many animals in my life, lol. I have been smoking on one type of a smoker or another for many years, fed lots of people and this is just
MY opinion. I say do what works best for you!