There are many ways to do them. All I can share is what I do in my WSM or Kettle.
Spares: Try to get racks close to the same weight and thickness. 225-235F chamber temp. Water pan with only water. Spritz every hour to 90 minutes or so with something sweet that will add to the bark. I'm always playing with my spritz ingredients. Last used apple cider, peach schnapps, and Laird's Apple Jack. Drank the leftovers!. Check start checking for doneness by looking at bone draw and bend test at 5 to 5.5 hours. When nearing doneness desired lightly sauce and continue smoking for another 30-45 minutes.
The leaner BB's I foil with a 2.5-1-.5 at the same temp. They come out more consistently moist for me that way.
I prefer spares over BBs and do spares 90% of the time. Usually only do BBs when requested.