Question away - I'm an idiot right now, and I know it!!! lol
Ok, upon seeing the above responses, I'm figuring I'll knock it down to one butt. And... from the above responses, I'm figuring maybe I'll throw everything on around midnight. That way, if it would take 18 hours, it's still ready at 6pm!
Like I said, I'm not sure what size brisket I can get (without special ordering), so that may be a factor as well.
And yeah - this is (currently) a single-grate UDS, so I'm thinking I shouldn't try to cram it with more than I need.