Swordtails are like water bunnies, they will breed until you are up to your neck in babies, trust me, i dont have to go back to the store ever again, because i have so many...
Now, she dropped on Tuesday you says, and she is already preggy again, this is quite understandable, as you said, she may have stored the seamen from the male, in which case swordtails produce eggs rathe rapidly, and so she may have produced them and fertilised them with the stored Seamen already, or if she is in the same tank as the male, he might be one randy bugger and done it to her again, my male has four adult females around him, and he managed to get around to them all in two days...
As for your question on her getting bigger quicker, it aint a matter about how big she gets, the size she gets can give you a rough esitmation on the amount of fry you could get, the bigger, the more you will recieve if they live long enough, but put it this way, once she has dropped, she might return to her original size, however it does not mean she is finished either, swordtails dont always drop all their fry at the same time and so will drop them on intervals, which vary as much as guppies do in colour, mine drop on interval of weeks at a time, so drop with a hour of each other, you just have to watch out for this, its all based on luck
