Nice.....make it when the sun shines or the lights are on!!  What no,. claas?  I am always intrigued with indoor bunkers.  Several times we have had groups at our farm from Germany, Switzerland and Australia, and they have used the term "Clamp"  before, and I believe they are talking about a bunker, or pit, that is covered.  What do you use to pack and what are the dimensions of the bunker and how much clearance between the top of the walls and bottom cord of the truss.  I assume the roof is because of a wetter climate?  Thanks for sharing.