id say then around a 300cc implant to achieve that size or a bit smaller!! prob would fill out and make you firmer too!! i was a 34b and had 340cc and went up 3 cup sizes!! so rpbo around that size!! god yours would be brill!! proper big!! ha ha!!!! in the end i suppose it doesnt matter how big you are already, there loads women out there with perfect boobs and still have boob jobs! in the end its up to you!! i do like big boobs though! i wish mine were massive, but wasnt allowed any bigger, but maybe in the future in my late 30’s i may have another op and have bigger put in, as my skin should stretch a bit now X