Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See page_maxonapi_getting_started_foundations_cinema_parameters.
Parameter: Strength
MGDELAYEFFECTOR_STRENGTHParameter: Selection
MGDELAYEFFECTOR_SELECTIONParameter: Mode
MGDELAYEFFECTOR_MODEParameter: Position
MGDELAYEFFECTOR_POSITION_ACTIVEParameter: Rotation
MGDELAYEFFECTOR_ROTATION_ACTIVEParameter: Scale
MGDELAYEFFECTOR_SCALE_ACTIVE