Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Polygon Type
MDATA_CLOSEHOLE_POLYTYPE
Parameter: Patch Rotation
MDATA_CLOSEHOLE_ROTATION_OFFSET
Parameter: Patch Width
MDATA_CLOSEHOLE_WIDTH_OFFSET
Parameter: Basic Polygon Type
MDATA_CLOSEHOLE_BASIC_POLYTYPE
Parameter: Create Tri-/Quadrangle
MDATA_CLOSEHOLE_TRI
Parameter: Select New Polygons
MDATA_CLOSEHOLE_SELECTNEWPOLY
Parameter: Select Outline
MDATA_CLOSEHOLE_SELECTOUTLINE
Parameter: Phong Break Outline
MDATA_CLOSEHOLE_BREAKOUTLINE
Parameter: Close All Holes
MDATA_CLOSEHOLE_CLOSEALLBTN