Most people that have the cabinet probe loose place under and to the side of the lowest rack of meat being smoked. If the lowest rack of meat is the second rack then it goes just below it.
There are others who use a fixed position for the probe usually on the back wall.
With the probe below the meat you get a better reading of the temp the meat is
being smoked/cooked at.
If it is above, then the meat could shield the probe and you could be smoking at
a higher temp than you really want.
But it looks like everything came out OK.
