Here are the morphs in the Netherworks "Laura" set:
DAZ Styled: Tone, Muscular1, Heavy, NeckThin, ArmsPetite, ShldrSmall, BicepFlex,HipNarrow, HipSmall, TummyOut, WaistNarrow, GluteBig, GluteSmall, Glute Raise R, Glute Raise L, ThighFull, ThighInFull, ThighWide, KneeSmall.

eXpansion Styled: Fey, Thin, Mature, ArmsLite, ArmsBig, ShldrThickn, ForearmThickn, UpperWidth, UpperDepth, BreastSize, BreastUpDown, BreastTogether, BreastWidth, BreastHeight, BreastOut, BreastTurn, WaistWidth, WaistDepth, LegsBig, LegsLite, ThighThickn, ShinThickn, CalfFull, CalfBulge, CalfFlex.

 I would think that "Fey, Thin, " would decrease the cup size. also a minus on "BreastOut, BreastSize, would also decrease the cup size.

cheerio  lululee