I was able to assemble a second section to the tower mock-up this weekend as well as implement a few of the structural recommendations made by my friend Dihong Shao.
The inner tube lashing technique continues to look promising - it has the marvelous ability to keep the connection tight even while being wrenched around. I'll probably end up doubling the tubes where they connect the vertical sections together - just for the redundancy. I've added two tension lines to each of the square plan sections. These prevent the squares from deforming into diamonds. I also realized that these tension lines can be added to all the squares before the trip to the Playa - greatly reducing the amount of work that will have to be done upon arrival!
I managed to break one of the vertical poles while attaching the second section - this was before any tensioning and bowing. The pole broke right on one of the nodal ridges - which makes me think it must have been rotten or already cracked. Now I test each pole for structural flaws before I use it!
The second image is a view from the bottom of the first section as it lays on its side. I love the graphic geometry of this point of view.