Pull it off when it hits 203 degrees and it is perfect. You can pull it sooner, but it doesn't shred nearly as easily. The 1 hr/lb almost always get you right at 203 on time....sometimes it needs to go longer or you need to raise temp a bit at the end if you want to speed it up.

If you are trying to time it, you can give yourself an extra hour or so and just keep it wrapped in foil in a cooler until it is time to shred.