Nice butt, Papa Payne!
SirDanK, I would suggest that you try doing butts different ways for yourself to see what you prefer. Everyone's taste and cooker is different. All of these methods produce result that will be better than you can get at 90% of the BBQ restaurants out there!
Here's my take on fat up or fat down. If the heat source on the cooker is below the meat, and the exhaust is above the meat (like a UDS or WSM), the airflow will be generally vertical. Having the fat cap down protects the meat from the hot sir and help keep it from drying out. If the heat source is off to one side of the meat and the exhaust is on the other side (like a traditional offset or a reverse flow), then the airflow will be primarily horizontal and the hot air will be moving across the top of the meat, so fat cap up will help keep the meat from drying out.
This is my theory and may or may not be right :-D It makes logical sense, but in some empirical testing that Big Mista did in his Spicewine with briskets, fat up or fat down didn't make a difference in the finished product. Fat down did require more clean up after the cook.
As far as foil, again, personal preference. At home I generally don't foil until the meat is ready to rest after the cook, but for comps I do foil (based on bark color, not temp) and I take this opportunity to add additional flavor to the product. In either case I cook the meat until it feels done (probe slides in like into warm butter), not to a specific temp. Each piece of meat is different and I have had to butts or two brisket that were within a couple of ounces of each other take considerably different times to get to the right feel.