Please help me decide on an implant size Sientra 385 or 410 mods ? Surgery in two weeks (Photo)

A few rules of thumb about breast implant size: 1. The implant cannot be wider than the existing width of the breast, an needs to be a little bit narrower because the measured width is external (so a 13 cm width implant in a 13 cm wide breast may not be a good idea); 2. Most patients would choose to go a little bit larger if they had to do it all over again; 3. a 25 cc difference is less than 2 tablespoons, not very significant; 4. work with your plastic surgeon and rely on their experience and expertise to guide you. Your breasts appear to have a slightly oval base, which means the vertical diameter is less than the horizontal, which in turn means the wider implant could be problematic. Everything involves trade-offs.

Thank you for the question.  Despite your good description of goals, online consultants will not be able to provide you with specific enough advice to be truly helpful. Ultimately, careful communication of your goals (in my practice I prefer the use of goal pictures, direct examination/communication in front of a full-length mirror, and computer imaging) will be critical. Given that your surgery is coming up soon, I would suggest that you schedule additional time to spend with your plastic surgeon communicating your goals, preferably prior to the date of surgery.
Generally speaking, the best online advice I can give to ladies who are considering  breast augmentation surgery ( regarding breast implant size/profile selection) is:
1. Concentrate on choosing your plastic surgeon carefully.  Concentrate on appropriate training, certification, and the ability of the plastic surgeon to achieve the results you are looking for. Ask to see lots of examples of his/her work.
2. Have a full discussion and communication regarding your desired goals  with your plastic surgeon. This communication will be critical in determining  breast implant size/type/profile will most likely help achieve your goals. 
In my practice, the use of photographs of “goal” pictures (and breasts that are too big or too small) is very helpful. I have found that the use of words such as  “natural” or "full C or small D cup” etc means different things to different people and therefore prove unhelpful.
 Also, as you know, cup size varies depending on him who makes the bra; therefore, discussing desired cup  size may also be inaccurate.  Again, the use of computer imaging has been very helpful during the communication process, in our practice.
3.  Once you feel you have communicated your goals clearly,  allow your plastic surgeon to use his/her years of experience/judgment to choose the breast implant size/profile that will best meet your goals.  Again, in my practice, this decision is usually made during surgery,  after the use of temporary intraoperative sizers.
I hope this (and the attached link, dedicated to breast  augmentation surgery concerns) helps. Best wishes.