Hi! The vintage size has the french clips/omega backs which I love. I've tried la pousette backs and to me, they are so so so cumbersome. I can't get them right half the time, and it's annoying. They are mostly associated with smaller earrings such as the Sweet or mini Frivole, so add on top a small earring, a tiny la pousette disc, and I'm a clutz.
If earrings back matter to you (they do to me), you can check the earrings you like online and there are photos that show you what type of earring back.
Good luck!