I did a rib roast for the whole family at Christmas last year. I didn't specifically follow the linked recipe, but it was very close to what I did. The biggest difference was I pulled the roast off the smoker 10F shy of my desired temp and let it rest for an hour. During this time the temp rose to where I wanted it for doneness and then started cooling a bit. That's when I did the high temp sear to brown the exterior. I used the WSM, removing the middle section and putting the top grate right over the coals. While I was making the necessary adjustments the coals got plenty hot. Too hot, really. I ended up more singeing the outside than browning it. The 500F oven might be a better alternative. The idea behind the long rest before searing is so you aren't applying massive heat pressure to the exterior right after pulling it off the smoker. Let it stop cooking first and then brown the outside. This will keep it from going well beyond your desired level of doneness.
With a large enough roast you can actually hold it for several hours before doing the sear. I miscalculated the cooking time and the roast was ready to pull hours before I had planned, so it sat on the stove covered with foil for about three hours. After searing it was still plenty warm for serving.
Oh, almost forgot. I trimmed and tied the roast and salted the exterior 48 hours before cooking. You could use Montreal Steak instead of plain salt, or mix some herbs in with the salt if you prefer that. I let it sit, uncovered, in the bottom of the refrigerator on a rack in a baking sheet. You lose a bit of moisture this way and concentrate the beef flavor. The salt works its way well into the meat. It also forms a pellicle on the exterior that holds on to the smoke really well.