I was interested in finding out the actual numbers for RvR kills in the lakes across different days and timezones, so I got the statistics from the killboard for the last week, and graphed them. As an average of the entire week, it looked like this (times in hours based on Altdorf timezone):

Nothing really unexpected, most of the activity is in the evening, order has a slight advantage during the day, destro has a slightly larger advantage in the evening.
In the following spoiler I also have separate graphs for every weekday. Also nothing too surprising, by far the most action is on Sunday (although interestingly enough it's still very concentrated on the evening), with Saturday below it and then the entire rest of the week.
If you're interested in the raw data to do some of your own statistics, I uploaded the kills as a collection of CSV files here:
https://mega.nz/file/8fY0RZQD#1rhRm09yJ ... HM6bw6-fTA