I highly subscribe to the ''beanbag/egg timer'' thing, but recommend 20 minute bits. And do not fear, there is an old saying: When you''re tired enough, you''ll sleep. A modern supertanker or container ship can be on you, from the horizon, in twenty minutes, and contrary to the warm and fuzzy thoughts of some folks, they will not stop to look for survivors even if they do realize they hit you. You are a problem of monumental dimensions if you survive, a blink in the eye of misfortune if you don''t. You are responsible in all ways at all times to avoid collision, and taking that to your heart helps you adjust to the overnighters. Do not dread it, it''s not nearly as bad as you might think. Practice at home. Do it for a whole night. And get up, walk outside and look around, then go back to bed and set it for another twenty minutes. You''ll see. You can adapt and adjust, and actually get plenty of sleep. Then do it durung the daytime and stay up all night. It can be easier to blink out during daylight when it doesn''t seem so lonely or scary. Of course, on a clear, moonless or slim phase night, the stars are unbelievable and it''s great to use a starfinder and get familiar with the heavens. I personally love Orion, nebula and all, the Pleiadies (sp), and the Andromeda galaxy, M31. You can see the whole milkyway, the other planets and the space station. It''s a pretty good show.
You will still be exhausted after seven days, but that has more to do with the endless motion of the boat than a lack of sleep. The only way to combat that, is conditioning. Eat well, drink plenty of good water, avoid alcohol and drugs of any sort, stay active and fit, and try to make your position in the cockpit as truly restful as possible. I have a tendency to get lazy and start eating cold Dinty Moore beef stew out of the can. True, it provides nourishment, but it''s better to heat it up and have water with it, as well as maybe a cup of coffee or tea. Treat yourself as though your enjoying the trip, not enduring it. And keep busy: read, listen to music, sew, splice
lines, wash laundry in a bucket, check and mark your position on a chart, record position, speed and other things. Don''t sing - distance from land doesn''t improve your voice and provides a startling dimension to your remoteness that you might want to avoid. I used to roadrace motorcycles and we knew to never look at the walls to see how fast we were going. At sea, I never test to see how alone I am. Niether of those bits of information have anything good to offer.
A single handed sailor has to confront and adapt to a few special aspects of thier chosen lifestyle that will either make or break the dream. I suggest small bites at the apple. A seven day over-nighter for a first passage sounds a little daunting to me. I would think a single, then a double or triple, then more. Enjoy the learning curve. Be truly prepared both mentally and physically for that first seven day passage. Get there with a broad smile on your face, not like a desperate survivor of a grueling ordeal.
Just a thought.