In my UDS, I never use a water pan. I have found that the environment here + the meat make the UDS fine on humidity levels.
For butts and briskets I don't ever use a fat catcher. I typically will let them sit on the pit for 4-5 hours (once the bark is set and the color is good), then wrap. I love the sizzled fat flavor on the meat, but it can be overbearing if you don't wrap your meats.
For poultry and ribs, I will use a fat catcher (normally just foil on my 2nd rack). I don't like the flavor of the sizzled meat on poultry or ribs. I will always use a fat catcher and also I do wrap if the color starts getting too dark.