Physical exercise seemingly makes little difference, but a day of learning can mean a good sleep.
Exactly. I think this is the key and why writing has been a godsend (there is no god) for me. I get to empty my brain, wear it down a little before sleep, so it is happy to wait until the next day to think again.
8 hours is a dream - I can do it, but I go to bed too late :)
I've been trying for 10pm, usually head down for 11 latest. It's working a little - still waking up before 6 but I have scraped 6 hours the last two nights.