I managed to get the construction done on my module, I built it as two four foot sections for transportation purposes. As I mentioned the inner joint has copper tubes to help align them, basically to make it easier to get that joint lined up at setups.
For the legs I created a pocket out of pieces of leftover plywood, they actually stick out about 3/4″ below the box frame. This was intentional for two reasons, first the scraps I had were six inches long and they make a mini stand to keep the module just above the floor when it’s stored on the floor and won’t pinch any hanging cables. This is an idea I picked up at the Westminster show from someone else’s module.