415cc high profile or 445cc ultra high profile? (photo)

While it sounds like you are starting in the right size range, I would reserve any recommendations without a physical exam to assess your soft tissues. The Ultra High Profile breast implant will provide more upper pole fullness and provide more roundness to the breast. The Ultra high profile implant is not a commonly used implant because of the unnatural result it typically gives to the upper pole of the breast. 

Thank you for the question.  Based on your photograph, I think that you are starting at a good place and should have a very nice outcome with breast augmentation surgery. It is true that ultra high profile breast implants have greater projection; I find these implants to be very useful for patients who want the "round look".***Given that your surgery is coming up soon, I would suggest that you spend additional time communicating your goals/concerns directly with your plastic surgeon, preferably prior to the date of surgery.  As you know, it will be important for many reasons, that you feel comfortable that you and your plastic surgeon are on the "same page" prior to proceeding.  Show your plastic surgeon what your goals using as many visual aids as possible.   As you can imagine, terms such as "natural" or "fake" can be interpreted differently by different people. This additional communication will go a  long way when it comes to helping alleviate your anxiety prior to proceeding.

  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. For example, I have found that the use of words such as “natural or fake look” or "C or D cup” etc may mean 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  helps. Best wishes for an outcome that you will be very pleased with.