Throw down to second is the same with righties and lefties. Biggest advantage for lefty is the throw to first on a bunt but like teddy said with so many left handed batters and speed teams the bunt coverage is huge. A good catcher left or right is important.
yes, the throw down to second is the same distance, but if the majority of the batters are in the left side of the box then the majority of the time the right handed catcher is having to throw around someone. keep in mind that none of this discussion matters unless the girl can field her position properly, has a great arm, and can hit.