So we had 18 people and it went 30 rounds. I had matchplay only picking our faster playing games for the most part to speed things up. We also made a decision (with the agreement of the players before hand) to award multiple strikes to the loser of each game when it was down the final two.
It still took a few rounds of just the final two to declare a winner, and we relied on pen and paper to keep track of strikes at that point. We still used matchplay for arena draws.
If we didn't do this I think it could have gone a max of 11 more rounds if only 1 strike was awarded per loss.
Also we used swiss pairings to try and force the top of the field to give each other strikes throughout.