I have used combinations of male and child morphs to get smaller breasts... these exist for both V4 and V3. Perhaps using a flat chest like that and morphing the breasts back out with magnets or morphs would work. Long ago IssacNewton I think made a "Ando" morph for Posette that was a "neutral base" to morph new waist and breasts out from again.

Jules, that Lulu is very nice. Realistic small breasts.