Can my body fit 600cc High Profile silicone? And should it be under or over the muscle? (Photo)

Thanks for your question and photographs.  It is difficult to answer your question without an in-person exam.  Depending on your base width, you may be able to accommodate a 600cc high profile implant.  On your small frame, I believe this would deliver the "fake" look you desire.  You appear to be fairly thin, so a submuscular placement may be better for your to help minimize risk of visible wrinkling in the upper pole of the breast.  I would seek out a board certified plastic surgeon in your area for an in-person consultation to better answer your questions.   Good luck. 

 Thank you for the question and pictures. Based on your photographs, I think that you are starting at a good place and should have a very nice outcome with breast augmentation surgery. Generally speaking, I think that it is in most patients' best interest to have breast implants placed in the sub muscular (dual plane) position. You will find lots of information about the pros/cons associate with different breast implant positioning on this website.
Otherwise, unfortunately, online consultants will not be able to provide you with specific enough advice (regarding specific breast implant size/profile) to be truly helpful. Generally speaking, the best online advice I can give to ladies who are considering breast augmentation surgery (regarding breast implant type/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. In bra sizers can be useful communication tools also.  For example, I have found that the use of words such as “natural” or "D or DD cup" or "fake look" etc means different things to different people and therefore prove unhelpful.
Also, as you know, cup size varies depending on who makes the bra; therefore, discussing desired cup size may also be inaccurate. The use of computer imaging may be very helpful during the communication process.
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 for an outcome that you will be very pleased with.