heads up for your install ... when mounting the bracket that the "L shaped brass" piece goes to, your tolerances are fairly tight for any type of socket or box end wrench. I have a fair collection of tools, and I didn't have "the right tool" for this. If I had noticed before hand, I would have run to the hardware store and gotten something with a different head on it (similar to the allen keyed one with the L shaped piece) to allow me a better purchase on the screw.
I was able to do an okay job with a small crescent holding the nut on end while I turned the screw. Good luck ...