I'm a bad example, so just ignore me. However, to me a fatty is a Jimmy Dean sausage. I have no idea where I got that, but maybe my wife read it or saw a picture. We've cooked them up with maple syrup on them (great carmelization) and always with a rub. We cook to an internal temp of 170 degrees. usually 2-3 hours at 225 in our WSMs. Put them on Thomas English Muffins with an egg and you have an Egg McFatty.
Foil: I do the 3-2-1 for ribs and it's pretty good. If my ribs have an attached brisket that I cut off, i've sometimes not foiled the brisket and it's tasted more smoky and been dried out a little. I foil my butts if its taking forever, like 9+ hours and still sitting in the middle of a stall that's worse than Congress trying to impeach someone. I do like foiling the butts so I can collect the juices and toss back into it when I pull it. I get my pulled pork really moist and mushy. No dryness here
Foiling beef brisket for several hours when you pull off the smoker so the juice gets all redistributed before slicing is good too.