See my reply to a similar question
this post.
As you guessed, folks will register and we will assign starting waves based on their qualification time. Exactly which times will get you into which wave will depend on who signs up. Also note that there may be more than two waves. The initial crowding along the first few miles of the trail is one of the largest grumblings that I've heard over the past few years and hopefully some of that will be addressed by reworking the start procedures. The other complaint is how slow folks go at the top due to a lack of oxygen, but then we can't do much about that. :-)
--john