Hi KLynch and welcome!
Measuring temps in ribs is near impossible. If you can find thick enough meat, you will need to get them up around 190-200?.
BUTTTTT, that is a bad way of measuring doneness....much too inconsistent.
Instead, take a toothpick or other probe and slide it between the rib bones. It should go thru easily. Most folks need to cook their ribs longer to get a nice tender bone.
I am an avid user and firm believer that foil will turn out the best ribs. I smoke for 3 hours at 225?, then foil and cook agaon for about 2-3 hours then take out and sauce and back into the cooker for 30-45 minutes. That totals 6 hours for a 2 1/4lb. slab of baby back ribs. Spares take even longer.
Of course, there are many who do not foil and their ribs are still very good.
It just takes some practice and some experimenting.
Have fun and good luck!