Is it just me, but isn't it a little early for deciding who are "A"s and "B"s without knowing the post position draw?
I don't think so, given the amount of horses and races, getting organized now can only help, and that isn't to say that you can't upgrade or downgrade from A to a B.
IMO, it is hard for a horse who is an 'X' to all of a sudden become playable.