My first op 380 highs, developed issues, second op 345 mediums (not my choice!) and have massive issues
I know what you mean, if you have big implants it will give a better cleavage then smaller ones, no matter the profile, but yes high profile are narrower, medium are wider and don’t project as much (so you may have a slightly better cleavage look out of bras but measure smaller) again with lows, you will measure smaller
It isn’t always the case though, as your body may not be suitable for a wider base, so having highs will give you a natural look, cleavage or no cleavage xx