What's the perfect size breasts for a woman?

Subjective. For you or for your sig other? Don' t waste your time to please your partner. It's more important to know what you want. Living a life to please others won't make you secure or happy.
The French say the. Perfect breast fits into a wine glass. Some say any more than fits in a hand is a waste. The typical american male says bigger is better. The point is that different cultures and different people feel differently about breast size and there is no right answer.