We wanted to build this piece for so long, but couldn't find 1/2" metal anywhere. Mind you, we live in a pretty small town. We finally just decided to use 1/8" Metal, which works just fine in my opinion. We followed the rest of the tutorial, but I find that they don't go over how to install the metal at all. That needs a tutorial all on its own. We improvised with what we had here in our small town. We ideally wanted to find old metal, but that didn't happen. So we bought new steel, spray painted it & then beat it up so it looked more vintage.
I'd say hanging the barn doors & the track is the longest part for sure.