What Size 380cc or 450?

hello

In october I am planning my breast augumentation and still not sure what size I should go... I am 163cm high and 54kg and I am wide (in chest- size of implant 12,5cm base). My doctor said that I should go motiva ergonomix 380cc demi or 450cc full profile. Now I have 75B ( before two kids it was 75C. I would like to have nice natural looking breast, and I am afriad of high profile to not get unnatural push up effect in my upper part of chest (my chest muscles are not small and are visible). Please help me, I want nice full breast but not veeery big and round on the top( round under of course). Implants will be under the muscle, incision under. thanks