re: About to do a pulled pork cook. Advice would be great

Do Not trim all of the fat cap off. If you want to trim it a little, go ahead, but they usually come from the store pretty sufficiently trimmed. Go fat cap side up, as it renders it will effectively baste the butt. Trim off any loose ends of meat that are sticking off, they'll just burn up. I'd suggest rubbing with olive oil over mustard, but that's your prerogative.