How many hours of dark are you planning on having? If you are seriously traveling, then you want to use all available daylight for traveling. Cooking, eating, and breaking camp all happen in the dark (take a good headlamp). That means:
*) Make camp as late in the daylight as you can -- it should be dark when you are done -- any sooner and you have wasted precious daylight. It's not hard to imagine supper taking a couple of hours by the time you melt snow for water, cook supper, and enjoy supper with friends.
*) Wake up a couple of hours before daylight -- it's not hard to imagine most people taking a couple of hours to cook in the dark, eat breakfast, and get their packs packed for traveling by daybreak.
*) That means you have approximately (dark hours - 4) for sleeping. Is that really too much time for sleeping if your day was pretty strenuous? Perhaps in the Arctic or parts of Alaska, but not over most of CONUS.
That does assume you are in good enough shape to enjoy strenuous traveling for (daylight hours) per day.