You should make it clear what sort of size you want.
Don’t be shy if you want big boobs make that clear, a lot of us seem to end up stressing natural, and to a surgeon I think “natural” means smaller then we think when we are talking to them so if you say you want to look natural, then you possibly aren’t going to get the size you want stress what result you want, also do you want to look an E/F clothed or naked, as most girls say they think they look smaller when clothed… if you want to look LARGE when clothed make that clear 🙂
It’s all about telling him what you want, and not letting yourself get put off by the conversation. Listen carefully if he says something doesn’t suit your body type then bear that in mind, but really in the end I guess it’s down to what you want and what he’s willing to do.
The worst thing seems to be people being shy, then going out and thinking i wish i’d asked more… Don’t be afraid to ask questions, he’s heard it all before 🙂