I followed the Cook’s Illustrated instructions but didn’t do a preliminary reverse sear, I did a short broil afterwards – and I’m not sure I needed that. I salted beforehand. You don’t need too much salt. I wrapped tightly in plastic and wrapped that in foil. It was in fridge about 18 hours. I took it out 1 hour beforehand.
My piece of meat was approximately an 8 x 6 inch rectangle. 250F, checking temperature every hour. At 1 hour the internal temp was 80F. I’m going by memory so I might be a bit off. I lowered the temperature to 200F. Internal temp was 130F at 2 hours. I took out meat, rested it, and ½ hour later put it back for 5 minutes under the broiler.
In retrospect I didn’t need to do this. The surface I broiled (which was on the bottom in the oven, fat layer on top) was already browned, and I didn’t care about the sides as they were outside slices anyway – and they were nicely browned, not gray. After 5 minutes under the broiler the internal temp was 137F. That was a bit overdone to my taste but meat was still pink, so not all lost.
I sliced very thin. Juice came out of meat for at least a day afterwards - interesting. There was one large vein of fat running through the meat and numerous tiny ones. Also interesting.
If you must broil, roast until 120 degrees. Personally, I’d simply roast to 130 and forget about the broil. Also, I’ll put the oven at 200F and keep it there. That is the lowest my oven goes. I’d salt a bit less.
Overall, it was a qualified success.
Thanks to everyone who helped me demystify this process.