Again a very nice piece! I would not put percussions on it. Just don't hear it to fit. The melody in itself is so rhythmic. I would like to hear though a not too crowded very low deep bass rhythm on it and also a wind hizz through the song. Not a melodic wind but just a wind with hall effect blowing with small alterations and changing to a more powerful in the end. It could give the feeling of big space. Or just leave it as it is. It sounds complete enough to me.