Motiva implants: should I consider round or Ergonomix? (Photos)

A bit about myself, I'm 20 years old, 163 cm and weigh around 54 kg. I've been to a surgeon a few times, he adviced me to take 310 cc full (this would fill in my breast perfectly, with my BW being 11cm) from motiva and he would place them dual plane. Now there are 2 options, ergonomic (which would look more natural) or round (which would put more volume in the top). Which implant would be advised for me? (I like natural, but would also like some volume, as I don't have that)