Poecilotherias are rather difficult to sex this way because the genus has very prominent male accessory organs. I've even seen breeders get it wrong.
That said - @cold blood I posted some good dorsal pics of my 3 slings at 3" at some point and people had a hard time telling what is what. I'm not sure you can dorsally sex ornatas at 2". I know Advans thread but his pics are just beyond clear and well lighted. That's not so easy to reproduce.