Would 350cc moderate profile silicone (under the muscle) be a good size for me or should I go a bit higher? (Photo)

The best cosmetic result in any
particular breast augmentation patient depends on a variety of factors,
including: your individual anatomy, realistic expectations, a thorough
discussion with the plastic surgeon about the options, and an understanding of
the pros and cons of any particular implant choice. Proper sizing is not just
about the number of cc’s. The thickness of your tissue, breast dimensions which
include the width, height, and projection, as well as chest wall width all need
to be considered when choosing an implant. Trying on implant “sizers” of
various shapes and volumes while wearing a tight t-shirt, bra, or bathing sit
at a preoperative visit will help you and your surgeon choose the optimal
implant.
There are no manufacturers' standards for cup sizing in the bra industry. The
cups of a 32 C-D and a 38 C-D are significantly different. Cup size
varies from manufacturer to manufacturer and even within styles from any
particular manufacturer. There is no direct correlation between implant number
of cc's and cup size in any particular patient.
Keep in mind that following the advice from a surgeon on this or any other website
who proposes to tell you exactly what to do without examining you, physically
feeling the tissue, assessing your desired outcome, taking a full medical
history, and discussing the pros and cons of each operative procedure would not
be in your best interest. I would suggest that your plastic surgeon be
certified by the American Board of Plastic Surgery and ideally a member of the
American Society for Aesthetic Plastic Surgery (ASAPS) that you trust and are
comfortable with. You should discuss your concerns with that surgeon in person.

Robert Singer, MD FACS
La Jolla, California

You appear to have a tight skin envelope with a tight lower pole so a smaller implant would be better in your case for great result off the bat without excess upper pole fullness.  You may consider a high profile device for more projection but I would not recommend too much more volume.  Best wishes, Dr. T.