Maximum Cup Size Through Breast Implants?

Hello,
Some women want larger breasts. I find myself discussing risk with them as the risks do increase substantially as you go beyond a certain size. That size is relative to your starting point. Really large implants with little tissue to cover them tend to look pretty ugly over time and there are not many reliable ways to fix this if it were to happen.
Just be careful.

Beauty is in the eye of the beholder. Your original bra size, 30B suggests that you are a thin woman and stretching your tissues excessively will eventually result in large, saggy breasts. In breast augmentation, both the patient and surgeon have high expectations which include soft, mobile breasts, minimal scars, appropriately positioned nipples, attractive cleavage, proportionality and longevity. As a generation, we've all been imprinted on the Victoria's secret girls and think that all breasts should be full, high and tight, however the reality is that aging and gravity scupper the best engineering.
Be candid with your surgeon about your expectations and I would expect (s)/he would reciprocate. There are three aspects of a great result: preop planning, intraop technique and postop follow up. Do get a few opinions and if you hear a recurring recommendation on size, which is generally based on the chest wall (rib cage) breadth, quality of your breast tissue, your general height and weight, please accept that a beautiful smaller cup may be preferred over an outlandish cup, which requires a lot of maintenance.
As a plastic surgeon whose practice is heavily weighted in breast (Reductions, LIfts, Congenital Anomalies, Cancer Reconstruction and Cosmetic), I have learned from my large busted patients that large breasts cause musculoskeletal pain, especially on the shoulders. Additionally, women are limited on their clothing options and often subject to teasing from both sexes, as well as impacted with exercise. You should also factor in that your breasts will change with pregnancy, weight gain/loss and menopause. Involve your best confidants, spouse, etc. I am sure you will choose well.