Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Angle Limit
PHONGTAG_PHONG_ANGLELIMIT
Parameter: Phong Angle
PHONGTAG_PHONG_ANGLE
Parameter: Use Edge Breaks
PHONGTAG_PHONG_USEEDGES
Parameter: Create Normal Tag
PHONGTAG_CREATE_NORMAL_TAG