One thing I’ve found with my RHP is that the probe needs to be directly under the panel to get an accurate reading. Mounting it outside the actual dimensions of the panel rendered mine useless as it only heats objects directly in the path of the panel.

Obviously the closer you get to the panel with the probe, the more intense the heat will be. 90 degrees a few inches below the panel may only get you 80 at the surface of your substrate.

I mounted my probe at the closest surface to the panel that my snake could get to ensure it was safe. The probe is about 10 inches from the panel.