What cup size am I likely to achieve with 375cc under the muscle high profile implants?

Thank you for the question.  There is no accurate/reliable/predictable correlation between size/profile breast implant utilized and cup size achieved. 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.
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 "C or 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.

Thank you for your question.  As others have stated there is no exact way to predict cup size based on implant size because of the variability in bra labeling of cup size.  It also depends on the amount of breast tissue you have with the implant is placed under the muscle as well as the size of implant used.  There is and anecdotal rule that it takes 150-200 cc of breast implant to increase by 1 cup size.I suggest you consult a board certified plastic surgeon who can do a breast implant sizing system evaluation by placing various specially shaped breast implants into a non-padded bra so that you can see the look that you want to achieve rather than being focused on the specific cup size.  For more information on choosing breast implant size please read the following link:

This is hard to give you an opinion without an exam or at least a photo.  I would focus less on cup size on more on breasts that compliment your frame