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