Will 475 to 500cc silicone under the muscle look big on me? Which profile should I choose, high or moderate? (Photo)

The increase in implant size will increase your size by one to one and a half.  You will have more fullness on top, as well, which will more look un-natural, but this is what you like i assume.  Moderate plus will soften this and may add a little more to the cleavage.  However, the muscle limits the cleavage if the implants are underneath. Good luck

Thank you for the question and pictures.   You will find that online consultants will not be able to provide you with specific advice in regards to selection of specific breast implant size/profile. Ultimately, careful communication of your goals will be critical.
Generally speaking, the best online advice I can give to ladies who are considering revisionary 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” or "too big" 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.   
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).  Viewing the patient's chest wall in the upright and supine positions, with temporary sizes in place, help select  the best breast implant size/profile for the specific patient.
I hope this, and the attached link (dedicated to breast augmentation surgery concerns), helps. Best wishes.

You should trust your surgeon to pick the best profile that will fit on your chest.  As for size, its a personal issue and you should have had the ability to size in your surgeon's office to 'see' what you would look like with each implant.  If you like both sizes and looks, its always suggested to my patients that they go with the larger one and no one has ever complained about that approach.  Realize as you move your implants more medial, your nipples will shift outwards.