Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Use Fields
POINTSELECTIONTAG_ENABLEFIELDS
Parameter: Restore Selection
POINTSELECTIONTAG_COMMAND1
Parameter: Select Points
POINTSELECTIONTAG_COMMAND3
Parameter: Hide Points
POINTSELECTIONTAG_COMMAND5
Parameter: Select and Hide Others
POINTSELECTIONTAG_COMMAND2
Parameter: Deselect Points
POINTSELECTIONTAG_COMMAND4
Parameter: Unhide Points
POINTSELECTIONTAG_COMMAND6
Parameter: Tolerance
POINTSELECTIONTAG_FIELDTOLERANCE
Parameter: Use Deformed Points
POINTSELECTIONTAG_DEFORMEDSTATE
Parameter: Fields
POINTSELECTIONTAG_FIELDS