4. Finally, there are also a bunch of no-show people, who have reservations to hike but don't show up at all, and don't logon and cancel online. Their slots become available at 11 AM the day of the hike start. So if you show up at 11 AM, it is very likely you will get your permit and be able to head directly to the trail head. The unused permits numbers include all of these, too.
I doubt this is realistic for most people. I wouldn't want to start this hike at 12 noon and have to complete it that very day. The complete hike is tough enough, either via the mountaineer's route or regular Whitney trail. I enjoy the toughness of the hike, but I would prefer to enjoy the day as well, take a few pictures, enjoy time at the top, etc., and not try to accomplish a mad scramble up and down.