Ex U S A F here, 31st., 35th.,37th., and 52 TFW alumnus.
Jet Engine Mechanic.
No help for ya', but I do remember a build of the type you are speaking of.
P M "Shadetree" on here, as I think he mentioned building a "walk in" cooler, that might give you some guidelines.
Keep up the good work, and thanks for all you do.
You can have a beer on my taxpayer dollar ANY Friday, Brother! :cheers: