High Profile or Moderate Plus Profile Silicone for Narrow Chest?

Without knowing what volume ie: cc you are choosing, and what your breast diameter is, it is impossible to tell you how you would be best served.  The higher the pofile, the more the projection of the implant but the less the diameter.  Women who want cleavage are sometimes better off with the moderate plus, and women who want projection are sometimes better off with HP, but I say sometimes because it all depends on what volume implant you are choosing and what your breast width is.  This should be discussed with your surgeon.

You are right when mentioning measurements whem trying to chose the correct implant for you. Once the dimensions and skin cahracteristics of your breast are understood there is an ideal implant range for you. The profiles provide flexibility in achieving your desired breast aesthetic. This can range from "natural" to appearing obviously augmented. Photos of breasts you like but also breasts you do not like will help your surgeon understand the look you are trying to achieve. Review photos with your surgeon and be sure they understand your goals.

Generally speaking narrow breast width and shorter distances from the calvicle to the nipple do well with high profile implants.

I hope this was helpful. Good luck.