Breast Implant Size to Achieve Full D Cup?

It is very important to communicate your size goals with your surgeon.  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 cup” or "fake looking" 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.
I use  intraoperative sizers and place the patient in the upright position to evaluate breast size. Use of these sizers also allow me to select the press implant profile (low, moderate, moderate plus, high-profile) that would most likely achieve the patient's goals. The patient's goal pictures are hanging on the wall, and allow for direct comparison.
I have found that this system is very helpful in improving the chances of achieving the patient's goals as consistently as possible.
By the way, the most common regret after this operation, is “I wish I was bigger”.
I hope this helps.

SEE VIDEO FOR SIZING TECHNIQUE:
In reality 450 to 500cc does not represent a significant difference and if 500 is too big then so will 450cc. However, if 450cc is too small, then 500cc may be too small.
I would highly recommend that you stick with your sizing preferences. If you liked 400 then 450cc is an appropriate size. Try on a 450 sizer and if that is too big for you (correlates with a 500cc under the muscle implant), then inform your surgeon and he/she will not use this.
There are sizing techniques such as the rice test or zip lock or water filled condom or commericially sizers.

For your given measurements, I think that about 400-450 cc would accomplish your goals. However, with a wider breast diameter of 14cm, you may need to go with a slightly larger, lower (moderate) profile implant.