Here is some data if you want to go back and look at previous years:
May 10, 2016: 11:59:17 (Good Waitlist). I believe this year the timestamps for good WL were 58 and 59. Someone that year with a 3.92 gpa and email at 11:59 was accepted off WL, I was not. I'm sure there is more data there if you go back and look.
May 9, 2017: 11:37:49 (this was the year they got rid of good/bad waitlist). The timestamps were either 11:37 or 11:38 (someone could double check though).
May 8, 2018: 11:45:45 (Good waitlist). This is they year I was accepted off WL. In the first round of W