It's more about my own curiosity than anything. I keep thinking of different tourney structures.

The scoring of OFC makes lots of stuff possible. You could eliminate the brackets (not that there's anything wrong with brackets), if you wanted to. Each player could play against different opponents instead of playing only against a single opponent in each stage of the tournament. Then you could drop the bottom x% of the field and do it again.

I haven't ironed out all the bugs but consider this.
Each player plays n hands against each other player in HU matches. Once each player has played all n hands against each of their opponents, the leaderboard is culled to the top players (some pre-determined number advance).