Since this method is spawning so many critter, you might use a trick I used with my guild back in cata. I do not know if it have been posted, fixed or anything like that, but if you group up, a single critter kill counts for every guildmember in the nearby area. This way we were 5 people in the deeprun tram and got ~20k critter kills in an hour or so. So if any guildies are going afk, ask them to fly to your position and be afk there. So if you are in a group og 5, you will not get the 100 kills per wave, but 500. As I said, I do not know if it have been posted before.
Edit: Just found out that this method was already posted by Wickot about a year ago

Here's the link in case anyone want a more indebth guide
http://www.ownedcore.com/forums/worl...ters-hour.html (How to kill 20K+ critters in an hour!)