Really, the best time to release is when there's no-one else posting. However, if people discover such a time, all of a sudden it starts filling up with people posting at that time. In other words, those "best times" disappear very quickly after they are discovered.
Fortunately, the algorythm to display your series over on Novelupdates has been updated to always give you at least 10 minutes up on their site, so instead a good strategy might be to post when there are a lot of people over on Novelupdates to see your series during those 10 minutes. For this, the suggestion of posting at various times because there are people all over the world would be a rather good solution.
Finally, if you happen to have a lot of people who have put your series on their "reading" list, then it becomes a case where you should post your series as early after midnight UTC as possible. This maximizes the time you have to be noticed by your readers and will raise your view count, thus increasing your chances of hitting high on the "trending" list. Only use this last strategy if your readership is enough to get you on the first page of trending or even the top 9. If your readership is enough to hit the top 9 with this strategy, then it is definitely the most worth-while strategy because being on the main sites front page on the trending list will get you more new readers than any other strategy.
EDIT: (I have actually noticed that some of the biggest authors on this site will actually deliberately post at around 22:00 UTC, which is the time that will almost evenly distribute your viewer count across 2 separate days (balancing the huge rush in the first 2 hours against the gradual trickling-in over the hours afterwards,) thus lowering your ranking on the "trending" list. This probably indicates they are very good sports who do not want to hog the spot light away from the up-and-coming authors. In other words, they are already successful so they are deliberately avoiding the trending list.)
