its realy that simple Keep it on the same server
if you want to make it cross server fix the match making then make it so
there is no point for it to be cross server unless you are from a nonmerged server then i can say you might want it to be cross server
merged servers can do matsuri just fine ...
So keep it non cross server for merged server and cross server for non merged ones
a lot of ppl can't do there 5wins in cross server matsuri and they got match with some one who is like 20k higher power then them