As I reported in the past, I have used a combination of thermometers to understand the flow of heat in my stick burner. I have used surface grill thermometers such as the ones in this picture below:
And, located them like this:
I also use on every cook the Maverick ET-732 connected to the left hand side of the pit on the surface next to the chimney.
The one that I watch the most is this one on the lid.
What I found is this:
1. For the right hand surface grill thermometer, it can report as much as 350 degrees.
2. For the middle surface grill thermometer, it reports the same as the lid thermometer which is very interesting.
3. The Maverick is always 20 to 25 degrees lower than the lid thermometer. I watch this inside the house to alert me to fluctuations up or down that I can get up and respond to outside.
So, I trust the Lid thermometer for reporting the heat. The name on this thermometer is Yoder, but when questioned, I was told that it is made by Tru Tel. And it has a long stem. I do not have a second shelf for the long stem to bump into.
If you replace the thermometer with the Tru Tel, I definitely think that you will get a truer reading. I still think that you need to distribute the heat more evenly throughout the pit. That is why I added the heat management plate. If I had purchased the Old Country, as I had given that a good look, I was going to go to a local welding shop and have them make baffle plates for the Old Country. When the baffle plates are only six to eight inches wide, they are not that heavy and depending upon what you are cooking can be placed in different positions under the pit grill grate.
That's my $0.02 worth. So, it is up to you, but you need to know and understand your own pit. If you need to purchase surface grill thermometers or a laser surface heat reader, then do it. You will then understand placement of the meat product and what is happening inside your grill. And, this will help you cook a better product.
Ed