Hello Everyone!

My wife and I are hosting Christmas Dinner for our first time and I am going to be doing a Ham and Prime Rib Roast (very nervous and don't want to screw up dinner). I have a few questions on the rib roast.

I am going to be using the Serious Eats method of reverse sear. My questions are I have two different types of thermometers. I have a Thermoworks Pen and Dot, Serious eats says not to leave a thermometer in the meat and to use the Pen. I was always under the impression to use a leave-in thermometer to always get an accurate reading. Where is the best spot to pull the temp?

Other question I am going to buy tomorrow and then dry brine on Saturday, is that too long to keep the roast in the fridge? I am going to use Salt, Pepper, some rosemary and stick some garlic in the fat of the roast as well. How long do they usually take at 250?

And any recommendations on an au jus or sauce to serve with the Roast?

TL;DR - Nervous about cooking Rib Roast and need to know where to stick thermometer.

Thank you!