The use of sizers in your bra preoperatively does not accurately correlate with the size of breasts achieved with sub muscular implants. I think that it is very important that you communicate clearly with your surgeon to maximize the chances of achieving your desired breast size.
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” 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. 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.
I hope this helps.