So, I stopped by to see how this was going, and I decided to share my thoughts on how I'd restructure this if I were to do it again. Mostly, I would make it closer to double elimination rather than the existing "don't lose twice in a row." Everyone starts in A stream, but losing takes you to B. Once you're down to B stream, you can only get back in A for the final.
Note: a lot of these variant choices were difficult to make. I tried to go with balanced variants that weren't symmetrical or one SC each, and favoured variants with at least 20 finished games.
I would still have it start with WWIV, with 19 going to Haven, and 16 going to two games of Europe 1939.
The10 winners of Haven would continue to a game of Fall of the American Empire with the other 9 joining the top 8 Europe players (4 each) in a game of World Dip IX.
Things might get a little hairy at this step. My plan would be for the top 7 of Fall to go play Classic, while the other 3 join the World IX winners in a game of Fantasy World. The move to go play Classic feels a little awkward in my mind, and I really only include it just to have Classic somewhere.
Then, 5 of the Classic players go play Ancient Med, with the 2 losers joining the 6 Fantasy world winners in Sengoku.
The 2 Ancient Med winners go to the Final, which is a game of hundred. The third finalist will be the winner of a Rat Wars game played between the top 4 Sengoku players.
If I didn't make the move to go play Classic in A stream, I would have the top 5 Fall players head to Ancient Med, again with the 2 winners going to the Final (still Hundred).
During the Ancient Med game, B stream would play 2 games of Classic, with the top 4 (2 each) going to a Rat Wars game and the winner of that to the Final. Alternatively, to add a step between Classic and Rat Wars, you could have a Sengoku game with the top 4 from each Classic, and then the Rat Wars match to decide the third finalist. The advantage of this is that it avoids the massive cut from two Classics to one Rat Wars, but the downside is that it takes more time. To get the best of both worlds, you could have the top 4 from each Classic play two Rat Wars games, with the winners playing a two-player game (maybe Duo) to decide who the third Finalist is.
Those are just my thoughts, and since I don't plan to run this again, they really aren't worth that much, but there they are anyways.