Go build your own Mars Below kitbash ok y'all?!
Just kidding. There are double support because those pieces are the structural ends of the corridor builds (the sides and bottom are a U with the beams glued on either end). I guess I could redesign the corridors with out the timbers, just drop one of them in the middle or so for looks. That would sure speed up build time.
I really have no idea what I am building this for. I may expand the bottom pieces to 3" so there is a little more room for minis but I can still use this section as a back entrance to the mines. One end is already boarded up, I can put a bottomless pit blocking another, one end can come from inside the caverns and the last can be the secret entrance.
I dunno about mixing FL with this set. I kinda liked the idea of the rustic timbers and stuff mixed with the more modern buildings of MS. It makes it Serenity-like.