Lining up in person for Pokemon Cafe

Just finished unsuccessfully trying to get a reservation 31 days in advance online, anyone have any success with getting a reservation the day before online/day of in person? I noticed that spots opened up for the following day when I logged on at 6pm JST, so I am going to be trying that option when I find free time for myself while in Japan at that time.

If that doesn't work out, what are your experiences lining up in person? How early should I get to the cafe the day of? Are there usually always last minute cancellations available to take when you line up in person?