Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Create Tri-/Quadrangle
MDATA_CLOSEHOLE_TRIParameter: Polygon Type
MDATA_CLOSEHOLE_POLYTYPEParameter: Select New Polygons
MDATA_CLOSEHOLE_SELECTNEWPOLYParameter: Select Outline
MDATA_CLOSEHOLE_SELECTOUTLINEParameter: Phong Break Outline
MDATA_CLOSEHOLE_BREAKOUTLINE