Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Mode
MDATA_SDSWEIGHT_MODEParameter: Strength
MDATA_SDSWEIGHT_STRENGTHParameter: Set
MDATA_SDSWEIGTH_SETSTRENGTHParameter: Interactive Minimum
MDATA_SDSWEIGHT_INTERACTIVEMINParameter: Interactive Maximum
MDATA_SDSWEIGHT_INTERACTIVEMAX