Hi Chuck! Glad to have you with us!
In my opinion, the best place for the drop-in probe is in the box it came in. Personally, I hated that probe due to the inconsistencies that it caused. But, Dave likes it, and many are happy with it. To me, the wall mount probe is the only way to go...removes ALL errors caused by probe placement. You can get very different readings, depending on the box location.
Now, here's what to do: First, figure out how to mount the probe in the SAME location, for every cook. This should be toward the top of the inside, not touching the wall. Once you have a spot picked, mount the probe and run an autotune (download the .pdf file under the Auber Instructions section -
"How to Autotune the Auber"). When the unit is tuned, try to put the probe in the same location, every time. It's the only way to achieve somewhat consistent results with the drop in probe.