CFS and Bodyclock/Dawn Simulator

I have severe ME, and used a dawn simulator for a while. I'm not using it now because I found that I sleep better with a light mask on, but it was pretty useful before that, especially for getting me up when I needed to be up, and in a way that didn't make me wake up feeling half-dead (though you know ME, you'll still wake up feeling quarter-dead). I think I fell asleep a little more easily with it as well. I tried a Bodyclock first, but found the light was too dim to read by, so I sold it on eBay and bought one of the sort that plugs into a lamp of your choice. I do still use a bright lightbox every morning, though, as otherwise I end up with a 25 hour sleep cycle.