i think the PVP cross servers has their own mechanic, for an example 3v3 has a range of all server listed, since s1000++ can be match out with people from s20 ist. while GNW, Sage, and so on has its own cluster maybe its the same as space time. and yes the best way to figure it out is from GNW cross server rank and we are talking about huge number here, i mean it can be started from s800 ist to s1050? so the raw estimate is around 250 servers++ per cluster? this is only estimated, but u got the picture.