This is what I found from the reddit post "And finally, for those hyper-sweaty clans who want to prove that they are the true clan wars masters, we are planning to host a Battle Royale on that Saturday/Sunday, to be held in the Euro timezone so that Euro, EDT and PDT clans can all play against each other, in one particular clan war size bracket yet to be determined (but likely in the 46-54). Participating, placing and winning in this bracket will reap rewards and perhaps propel the victors to glory!"
No details on how it will work, except that it encompass large number of clans, leaves me wondering will it be node based, or will clans actually be in their own (party size) playlist? Well see.