We nailed it.
The problem with trying to master a food that you only cook once a year is that you only cook it once a year.
You forget what worked, what didn't.
In fact, in most, if not all, of our attempts with a standing rib roast, we've never got it so good that we wanted to even take notes.
For several years, there was the problem of the balky antique stove with erratic temperatures.
Then there was the new convection oven, but you had to adjust the temperature off-normal by 25 degrees... and was that up or down?
We finally got a decent meat thermometer, but aimed for too-high an internal temperature on the advice of somebody I will never name. No, never.
Then, this year Saveur's recent issue suggested roasting the meat with the ribs on top instead of on the bottom. And pulling it out of the oven when the thermometer reached 120ºF.
That seemed cold to me, but I made an important discovery. One that you proficient meat roasters probably already know. Bones are hot! You whip that baby onto a cutting board with a tent of foil over, and you have plenty of time to make your Yorkshire pudding. (Which I tried doing exactly as the recipe says this year, and nope, I'm goin' back to my profligate ways.)
I even had time to make some beef gravy, which we'll think of a use for later. Burp.
The roast finished its gentle cooking all by itself. All the way through.