Here is a very important tip regarding the installation of 12 x 24 floor tiles ~
The elongated tiles 6×24, 12×24’s etc have the possibility of arching or bowing in the center. In that case if you were to use a 50% split, you would be putting the highest point in the arch or center of the tile, against the lowest point or end of tile.
The Solution: Overlap 15% as seen here. Also recommended by manufacturers too.