Sorry for the long hiatus! It's been a really busy Christmas season this year.
So obviously there's no way today to change the seating algorithm. Currently, the algorithm uses at its heart a sorting algorithm with a number of "biases", such as which tables you've designated as first to collapse or last to collapse, or the number of moves a player has already made. Additionally, IF you've specified where the dealer button is, it will use that as its strongest bias. If I recall correctly, it will try to move a player from one table to another and place them in the same seat with respect to the dealer button, so that they are not penalized (which is generally true unless the tables have a different number of players, but that's an unavoidable consequence).
Adding in other seating algorithms should be possible. I'll just have to dig back into the seating algorithm, which is something I've been reluctant to touch for fear of breaking something. Truth is I need to add more tests to hedge against breaking it.
If I'm not mistaken, you're describing two different methods. Do the official TDA rules describe these?