determine first which country you have more players, and get the nearest datacenter for lower ping
btw, network analysis is a very deep job, you can have the nearest datacenter but with bad route, and the opposite too
i dont think that europe network infra has big problems like that, but in americas we have it all the time
an example of it is that miami for brazilians is the lowest ping for NA, but there are a lot of internet providers in brazil with bad route to there