Re: Tying Background
As I read your question you want to know what background to place behind the fly so your clutter and their colors don't interferr with your work. I use a piece of aluminum sheet metal 8-9 inches wide and maybe a little taller. I bend the metal on one edge so that I can put the "lip" under the base of my vise to hold it in place. I have one painted a light gray and another painted a medium to dark gray. Gray is the color photographers used to get their light readings. The light one for dark flis, the dark gray for light colored flies.
As for light I use several different lamps some for traveling some for home, just be sure you have enough light and the lamp doesn't get in your way when tying. I am not sure that the "100%" natural light lengths are not all that important in tying, only in taking color pictures.