What distinguishes ghayn and khāʾ?

Letter-by-Letter Qualities and Distinguishing Features

• Ghayn qalqalah, khāʾ ghunnah
• Ghayn tafashshī, khāʾ ṣafīr
• Ghayn low, khāʾ iṭbāq
• Ghayn voiced, khāʾ breathy