I'm not sure anyone will have a exact download time, unless they work for SE but, based on past patch and 2.0 launch experience.... They kind of do the downtime in waves, right now I'm sure they took down the server to update it with a very large server side patch. When they are down with that (hours), they will probably flip the switch on their side for the client update on our computers. At some point after they will probably be testing it out to make sure it actually works, then they turn it back on for us.

While other maintenance times have ended early, I'm going to bet this one won't. Reason being, is the massive amount of people that are going to log on all at once. They are going to do it as planned, on time, because that way all their staff can watch it like a hawk.

As far as size of patch, it will be very large. Probably atleast 5gb but probably as much as 15gb or more.