I am in.
I have all the expansions, but no promos.
In order to win a match, you must have won more games from the second seat than your opponent, with a minimum of one second-seat win.
I strongly approve of something like this because it helps correct for first player advantage, and having matches end in ties after 6 games is not a problem with Swiss.
One thing to clarify: does a shared victory count as a win or a tie?
The way I am interpreting the description, it would count as a win. So if 5 games were played between A and B, and A wins 2 games outright and B wins 2 games outright (all wins by first player), and the shared victory was when A went first, then the match ends after 5 games and B gets the match win (because B is first to three wins and has won more games from the second seat than A). However, if the first player wins every game outright for the first 5 games, then the match goes to the sixth game, and if the first player again wins the sixth game (so each player has won three games and no player has won from the second seat), then the match ends in a tie.