The main difficulty with the fence has been the weight of the metal, so in an attempt to counteract that, I place them so that they're partially leaning on each other, and duct taped together a bit. I ended up only using three of the pieces. The fourth piece was taller than the others and was entirely too heavy to stand up, and kept bringing down the other sides. I eventually ditched it, and just made a somewhat smaller fence.
To attach the letters, I strung some string back and forth between the spokes of the archway and put them up with duct tape.