On May 1, all the reservations that are still not paid up will be released, starting at 7 AM, at random times. There should be a lot more popping up that day.
Just a note of thanks, Steve. I did not get a spot in the lottery and happened to check back here yesterday. Noticed you posted the info above along with the permit links. I was able to get an overnight permit for very close to one of my original dates!