Sanders their are some really good packaged powder add water Au Jus out their to add too your roast. Get the low sodium ones if yah don't like to much salt.
Yup those wired meat thermometers are the way to go kind of fool proof. Mine broke have to get a new one. Just make sure the inserted thermometer is not touching any bones.
https://www.amazon.com/ThermoPro-TP-...eter+oven+safe
https://www.amazon.com/ThermoPro-TP-..._image_kitchen