Tony
This should help, me just winging it. 225* on the smoker and internal 135*
The below I used as a reference.
Use a digital probe meat thermometer for accuracy and smoke the racks of lamb to medium rare (135-140 degrees F). I have been using the Maverick ET-732 and I love the way it. It is a wireless remote meaning it has a sending unit that stays at the smoker with 2 probes.. one for the meat and one for the smoker. You put the receiver in your pocket or clip it on your belt and off you go. Whether you are mowing, napping or just piddling around with something else, you always know the temperature of the meat and the smoker and it has up to a 300 foot range.