Can't go wrong with 5.5 hrs for baby backs, and no peeking. Although, I usually take them out after 4 hours, dab'em up with some BBQ sauce, and then put them back in for the last hour or so. I dropped the foiling method several months ago, and everybody here is happy happy happy!
The spares will take longer.
As for the smoke around the door, this will end after a few smokes. I still see a little but of smoke around the door when I first start the smoker (now 11 months old), but it doesn't last long.
Have fun!