Syllables and Prayers During Guru Yoga

A while back I was at a workshop by a Yungdrung Bön abbot who taught Guru Yoga using a visualization of the Master with a crystalline body where you visualize being purified first by fire, then wind, then water followed by beams of light radiating from the Master's brow-to-your-brow, throat-to-your-throat, and heart-to-your-heart. When this happens and at several other points there are specific prayers and syllables that are prescribed. I found a similar version in _Healing With Form, Energy, and Light_ by Tenzin Wangyal Rinpoche which gives the ritual there, but without the strictly Tibetan elements. It clearly has the same bones (which is not surprising), but it doesn't contain the prayers or syllables. My question is: Does someone know the full version with the syllables and words intact (in any version, recognizing that there may be several variations) and/or a lead on where I might find it?