In my practice, implant size is determined by your measurements. I do not go outside of those measurements because the complication rates are significantly higher, and are not worth the risk.From your pictures, I believe that a 700c implant would be too big for your body--an in-person consultation with a BCPS would be best, rather than looking online. That should then give you an idea of what would fit your body/breast shape.Best.
The best way to determine implant size is to meet with a board certified plastic surgeon who is experienced in high-quality breast augmentation procedures. Your chest width and height should be measured as well as an assessment of your soft tissue, breast crease, nipple position, and other measurements. The implant should fit nicely in your breast without being oversized in an unattractive way. If your implant is too large or fits poorly, you risk implants which are way too high, may bulge to the side excessively, or with a damaged cleavage (uniboob). It is better to select the right size rather than the fullest possible because your breasts will be more attractive. Hope this helps!