I guess it all depends on the set and setting, as they are endless forms of meditations.

Singing indeed I find most beautiful. When I go in the overtones, it even happens to get mild CEV, it really puts you into that state of cleansing and you can get to that slow monosyllabic vibration that will lower all your defenses. Something that is present in breathing but quite differently, differently quiet the mind.

Gestures, not even as formulaic and precise as Yoga - more something like dancing in a sitting position - can go very well with the chanting/breathing.

You can also listen to a song you like, drink tea, draw something or write your intention if you have one and feel the need to exteriorize it in a still form. But I guess whatever you do, if you do it consciously, will be enough.

You should do what feels right in the moment.

Bog live!