Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Use Fields
POLYGONSELECTIONTAG_ENABLEFIELDS
Parameter: Restore Selection
POLYGONSELECTIONTAG_COMMAND1
Parameter: Select Polygons
POLYGONSELECTIONTAG_COMMAND3
Parameter: Hide Polygons
POLYGONSELECTIONTAG_COMMAND5
Parameter: Select and Hide Others
POLYGONSELECTIONTAG_COMMAND2
Parameter: Deselect Polygons
POLYGONSELECTIONTAG_COMMAND4
Parameter: Unhide Polygons
POLYGONSELECTIONTAG_COMMAND6
Parameter: Tolerance
POLYGONSELECTIONTAG_FIELDTOLERANCE
Parameter: Use Deformed Points
POLYGONSELECTIONTAG_DEFORMEDSTATE
Parameter: Fields
POLYGONSELECTIONTAG_FIELDS