A lot of how we chose implants is based on the base width of your breast. The same size in a moderate profile will have a wider base than in a higher profile, but the same about of gel, so that is how it projects more. We choose the profile of the implant based on how wide your breast is. To go higher, but restricted to breast width, we go up in profile.
The best way to decide is with your board eligible or board certified plastic surgeon, as it is based on physical exam. With gel implants, and if they are under the muscle, you have less of a chance of an "augmented" look, but the size / profile are based on your own anatomy