I tried to create a KO tournament for 128 players. At stage 1 everybody was supposed to play 1 4p game, first two players advance to stage 2. However, there is a restriction for 100 players per group, and even that doesn't seem to work properly. When I tried to create 2 groups with 64 players each, I get the same error message.
I don't know the reason for the restriction, but if it is the size and runtime of the algorithm to create the matches, wouldn't it make more sense to limit the number of games created instead of the number of players?
For KO tournaments like mine it has the added value that you see immediately who is moving on to the next round and who is out. Clicking through 32 is not very practical.