I think it depends on how late you can stay in a park. When the EMH time starts, the parks can be packed from the day visitors. As it gets later, more people start to leave and the lines will get shorter. It works the opposite way the EMH in the morning works. If you are there in the morning just as the park opens, you will be there with very few other people. At the night, if you can stay until it closes, there will be very few other people. This also depends on how late the park stays open. We were there at Easter and the MK was open until 3 am. We stayed one night and by 1:30 or so it began to get so empty that you could do any ride you wanted without much of a wait at all.