WK has no “new day” setting like Anki does (or maybe another system you’ve used). As others have said, it all depends on when you actually do your lessons and reviews.
If we call the new day 6AM, and that’s when you want your reviews, you should do lessons at 6PM, make sure to do the first review between 10-11PM, sleep, and the next review for those items will be waiting for you 8 hours later at 6AM. If you do that one on time, as Leebo said, the next review will be the next day at 5AM. And so on.
Outside of using seanblue’s vacation suggestion, the only way to shift when the big dumps happen is to shift when you do your lessons/reviews.
Hope that helps!