I hope you don't mind me saying so, but your little chirpers are going to perch on the light cord. So what I would do is to train the cord and support it with some wire so that if they do perch on it, it won't affect your light's stability or bring it closer to something flammable. Basically any electric cord is a perch to a chick. They love to "swing" on electric cords hanging in mid-air.
I'd also hang another support for the light (I recommend hanging lights two ways not including the clamp as chickens fly into it routinely). They will also perch on the metal guard under the light bulb but I have never figured out how to prevent that LOL.
Thank you for the help. I am new at this and am learning a lot from the forums. I would of never thought of that. What is your spacing for a roosting rack?? I think I am going to make it all one level.