How can I achieve a round, fake look? - Over or under the muscle? (Photos)

Currently have 600cc high profile mentor gel implants. Wantinf to achieve a round fake look with upper pole fullness ans a gap between breast. Ive triwd to achieve this look several times with failure . They always just redo the lift and they look the same. I’ve always had under the muscle but want some ideas on how to achieve the look I’ve always wanted. I am currently 47 years old and want that tight fale round appearance.