I don't know the setup of your grill, but I do know that you want the thermometers as close to the cooking surface as possible. Most aren't setup that way, unfortunately. I had to drill through my lid and add two additional ones. One on both ends, as mine is an offset.
I have the CG... the temp guage is as close to useless as it can get, especially where they located it. I have two 3" recalibratable guages - not installed yet - that will be installed at each end of the lid, close to the cooking surface. I have flipped the charcoal tray upside down to act as a baffle to help even out the heat from end to end, so the reason for two thermometers is to keep tabs on both ends of the smoker.
I also just got the Maverick ET-73 for remote monitoring of the chamber temp plus the meat.