I'm going with Chumley on this one.
I typically use my BGE for low and slow... and then convert it to sear if I feel it needs it. I have done a couple of large rib roasts, and find that 200-250 for about an hour and half per pound gets the internal temps to about 120F. I only sear if I haven't cleaned out the skirt and left the fat cap on.
I find if I score the fat cap, and give that a good thick rub, that it really doesn't require searing.
I also love to put a pan under with beef stock, a bottle of good red wine (decant into the pan for the procedural nerds), and a few onions, carrots, and herbs. If you are going long (past 4 hours) - make sure to top up that pan with a little water along the way. Then strain it when the rack is done and resting (at least 30 minutes) - drop the dripping into a skillet and reduce further (if needed). Then add a finely chopped shallot, some fresh thyme, capers, garlic, rosemary. Take off the flame and work a couple of big knobs of unsalted butter into a nice glossy sauce!
Finish a slice with smoked salt, and a small bit of sauce. And now I am intensely hungry...