So, the decision on the exact size of the implant that can be used for you can only be decided after understanding few more measurements. these would include the base width of your breast, nipple to infra mammary crease distance and other such measurements. However for you a size of 265-285 cc high profile implant would work well in the dual plane in all probability (again will need to check the thickness of your skin to know if there is any chance of putting it below the gland.) If you want a better cleavage, a practice that we do is to combine fat grafting to enhance your cleavage and your upper pole i.e. the upper area of the breast. I do not like very big implants as they look fake and can cause multiple problems in the long term.