Hello and thank you for the question.
While it may be reasonable to increase the size of your implants modestly, I would not recommend a jump to 800 ccs. Although I don't have the luxury of seeing photographs of your current proportions, it is likely that an implant that large will create anatomic unbalance. Additionally, over time, the gross weight of implants that large will impart undue damage to the soft-tissue, including stretching of the skin, potential disruption of the infra-mammary folds, development of excessive dermal striae or stretch marks. Keep in mind that some of the aforementioned sequale my necessitate the need for revision surgery in the future.
Before considering implants that large, I would recommend consulting with a Board Ceritified Plastic Surgeon who has ample experience with breast implant revision surgery.
Best,
Glenn Vallecillos, M.D., F.A.C.S.