1

League System

create only 1 division 1, with 4 people get demoted, for the other division powers of 2, also could 4 could work but only 1 would get promoted.
division 1 ->1
division 2 ->2
division 3 ->4
division 4 ->8
division 5 ->16
division 6->32
division 7->64
division 8->128
division 9->256
division 10->512
division 11->1024
division 12->2048
or
division 1 ->1
division 2 ->4
division 3 ->16
division 4 ->64
division 5 ->256
division 6->1024
division 7->4096
division 8->16384
division 9->65536
division 10->262144

this are numbers of leagues so multiplied by 20 the number of players.