Savannah,
Thanks for the kind words.
I got the adjustable floor lock from Amazon.
I cut a piece of pressure treated lumber to go between the shelf and the floor lock, and secured it with 3/8 X 4" carriage bolts (yes, I painted the wood and bolt heads black).
In case you were wondering, the box on the left is my version of a waterproof enclosure for my Tappecue V2.0.
It's allows the probes to be easily inserted and removed, and I am using a USB battery in the box instead of running to an AC outlet. A 5200 maH battery supplies power for 25 hours! Magnets secure the box to the cooker, and there is a dead-man cable as a safety.
I am working on a video of the box configuration, hopefully I will get to that over the next few days.