Size recomendations for implants for 11.5 BWD. How important is matching BWD to an implant? I'd like a natural look. (Photo)

Implant size is a very personal but crucial decision when considering breast augmentation. This decision is best made jointly with your board certified plastic surgeon as there are other considerations outside of patient goals/desires (chest anatomy/width, skin envelope, pocket dimensions etc...).
One rule of thumb is to fall in love with a "look" rather than a "cup." Cup sizes vary indirectly with implant volume (not to mention variations from manufacturer to manufacturer). The traditional teaching is that 150-250 cc (Note: wide variation) of implant volume is believed to correlate with a single cup size increase. Often times sizers or 3D imaging can be employed to more clearly define a patients goals. These tools can be helpful in bringing a patient's desires into line with the realities of augmentation. Communication is key.
It is important for patients to remember that volume option are defined by breast width. The implant size is tailored to the footprint of your native breast. Exceeding these measurements tends to lead to greater implant visibility (especially laterally) and compromises the "natural look" that  many patients are seeking. The larger the implant the harder it becomes to achieve the subtlety that is a hallmark of the "natural look."When sizing patients, there are a number of useful tools including:
-3D imaging (has the added benefit of offering a volumetric analysis of the pre-operative breast)
-Breast sizers (rice bags)
-Goal photos
With regards to your specific questions, it is important to remember that for a particular width there is likely more than one implant with variations in volume and profile. Your board certified plastic surgeon is uniquely qualified to guide you in selecting an implant that fits within your measurement parameters and satisfies your goals.Best of Luck!

Thank you for the question.  There are no hard and fast rules when it comes to diameter of breast implant versus diameter of breast (band width). In other words, these measurements are useful but are only one of the many factors come into play when it comes to selection of appropriate breast implant size/profile.
Ultimately, careful selection of plastic surgeon and 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, in bra sizers, and computer imaging) as well as careful measurements (dimensional planning) will be critical.
 
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 know words such as “natural or proportional” or "D or DD 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/video, dedicated to breast augmentation surgery concerns) helps. Best wishes for an outcome that you will be very pleased with. 

Some surgeons measure base width diameter and use this information in determining implant size. The problem is, this method often calculates small breast volumes. Other surgeons, myself included, do not use base width dimensions. I prefer to look at photos my patient provides (usually on her cellphone), and review photos of my patients with similar characteristics in my office. This gives me an idea of the best implant volume. I exceed base width diameters frequently and there is no problem in doing so. You don't want to be disappointed later that you did not go big enough. Remember, your breast size is your decision, not your surgeon's.  I attached a link to my website in case you wish to read more.