hi hun, i had my BA 2 weeks ago and went from a 34a to a D with 410cc with Marion Grob. it depends on idividual. i had unders as i didnt have much breast tissue so Marion suggested i go unders so it looked natural. i am really happy with them as they look nice and big when im wearing vest tops or dresses (especially with nothing on lol!) but wen im wearing certain clothes they are hidden and look smaller. it really depends if your wearing etc, figure hugging clothes.
i have a small frame from waist up so im glad i didnt go too big as it would look ovious and i would be paranoid incase people were lookin! i was just barely able to have 410s as they just fit in within my frame. any bigger they wd have started under my armpits lol!! hope you decide and all goes well hunnie xxx