I agree with Dr. Rand that breast implants are sized by the width of the breast wherever that is and do not make the breasts further apart or closer together. I would also agree that even properly sized, properly positioned (below the pectoralis muscle), and properly filled, they will still feel ripply on the outer side of the breast and underneath where the muscle doesn't cover (in thin coverage patients).
The main point that I'd like to make, though, is that high profile saline-filled breast implants are not the same in Mentor and Allergan. Allergan has low, medium, and high profile saline-filled breast implants that are scaled to the width such that a low profile implant gains about a cup size, a medium gains about a cup and 1/2, and a high profile gains about two cup sizes. The Mentor medium profile is essentially equivalent to the Allergan medium profile and their Moderate Plus profile is halfway between the Mentor or Allergan medium profile and the Allergan high profile, but the Mentor high profile saline-filled implant is not scaled for the width and if the same width dimension is used (as it should be) then the volume of the Mentor high profile implant will be much larger than a half cup increase as with the Allergan medium to high profile implant.
I have no commercial interest in this. It's just the mechanics of dimensions and volume. If a medium profile implant doesn't have enough forward volume for you then (in saline but not gel) choose the Mentor Moderate Plus as the next step up. If you want a high profile saline-filled implant then choose the Allergan/Natrelle one properly scaled to your breast width.