Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Strength
ID_MG_BASEEFFECTOR_STRENGTHParameter: Selection
ID_MG_BASEEFFECTOR_SELECTIONParameter: Maximum
ID_MG_BASEEFFECTOR_MAXSTRENGTHParameter: Minimum
ID_MG_BASEEFFECTOR_MINSTRENGTHParameter: Transform Mode
ID_MG_BASEEFFECTOR_TRANSFORMMODEParameter: Transform Space
ID_MG_BASEEFFECTOR_SPACEMODEParameter: Position
ID_MG_BASEEFFECTOR_POSITION_ACTIVEParameter: P
ID_MG_BASEEFFECTOR_POSITIONParameter: Rotation
ID_MG_BASEEFFECTOR_ROTATE_ACTIVEParameter: R
ID_MG_BASEEFFECTOR_ROTATIONParameter: Scale
ID_MG_BASEEFFECTOR_SCALE_ACTIVEParameter: Uniform Scale
ID_MG_BASEEFFECTOR_UNIFORMSCALEParameter: Absolute Scale
ID_MG_BASEEFFECTOR_POSITIVESCALEParameter: Scale
ID_MG_BASEEFFECTOR_USCALEParameter: S
ID_MG_BASEEFFECTOR_SCALEParameter: Color Mode
ID_MG_BASEEFFECTOR_COLOR_MODEParameter: Use Alpha/Strength
ID_MG_BASEEFFECTOR_COLOR_ALPHAParameter: Color
ID_MG_BASEEFFECTOR_COLORParameter: Blending Mode
ID_MG_BASEEFFECTOR_COLOR_BLENDParameter: Use Alpha/Strength
ID_MG_BASEEFFECTOR_OTHERALPHAParameter: Weight Transform
ID_MG_BASEEFFECTOR_WEIGHTParameter: U Transform
ID_MG_BASEEFFECTOR_UParameter: V Transform
ID_MG_BASEEFFECTOR_VParameter: Modify Clone
ID_MG_BASEEFFECTOR_CLONEParameter: Time Offset
ID_MG_BASEEFFECTOR_TIMEParameter: Visibility
ID_MG_BASEEFFECTOR_VISIBILITY