I'm a night person. I like to work between 2pm and 2 am the most.
I seem to work out my most difficult design problems late in the evening. Sitting quietly and meditating or doing something totally unrelated to my sculpting often brings a possible solution. But figuring out solutions to design issues in my dreams doesn't happen very often for me.
I used to keep a notebook by my bed, but it wasn't much of a help. I don't sleep for very long, but I sleep very deeply. I even get up and do things and even have conversations with my eyes wide open, but ... I have no memory of any of it. During these times, I filled the notebook with artistic gems like stick figures with word balloons that say "Cookies are good."
Working late at night also gives you the chance to catch old movies and have quiet time to yourself. Of course a movie like They Drive By Night is only good for the chance to see Bogart and to watch the rest of the cast chew through the scenery. I'm not sure why, but I was watching this movie when I came up with my first HexCat design. Maybe it was a gut response to the dog I was watching?