Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Polygon Type
MDATA_CLOSEHOLE_POLYTYPEParameter: Patch Rotation
MDATA_CLOSEHOLE_ROTATION_OFFSETParameter: Patch Width
MDATA_CLOSEHOLE_WIDTH_OFFSETParameter: Basic Polygon Type
MDATA_CLOSEHOLE_BASIC_POLYTYPEParameter: Create Tri-/Quadrangle
MDATA_CLOSEHOLE_TRIParameter: Select New Polygons
MDATA_CLOSEHOLE_SELECTNEWPOLYParameter: Select Outline
MDATA_CLOSEHOLE_SELECTOUTLINEParameter: Phong Break Outline
MDATA_CLOSEHOLE_BREAKOUTLINEParameter: Close All Holes
MDATA_CLOSEHOLE_CLOSEALLBTN