Just a follow up on the build.
I have discovered that there are is an aspect of the build that I would change should I do it again.
As detailed in the OT, I built metal panels to encase 2 inch hard insulation and just laid them against each other and secured them in place. I have discovered that without an insulating medium to seperate the metal panels from each other that the cooler air inside the chamber migrates, or conducts, to the outside.
If built again I would overlap the panels with some rubber or felt in between the panels to stop stop travel of cool inside - to the outside.
Other than that, it has performed flawlessly and I am quite satisfied with the build.
If you wait till the last minute to do everything, it will only take you a minute to do them.