Wallace's samatha practice, based on Padmasambhava: Am I doing it right? I have been practicing a path that may be too advanced for me, in that I'm not even sure if I'm doing it properly. It is a path outlined by Alan Wallace in one of his retreats.

The following is the relevant portion from the podcast transcript (it's a transcript of Session 1 - Settling the Body, Speech and Mind in its Natural State, from Fall 2014 Shamatha, Vipashyana, Dream Yoga, and the Experience of Pristine Awareness in the Great Perfection Tradition of Tibetan Buddhism):


  "[15:40] Then we turn to settling the mind in its natural state....Just for the duration of this session let your awareness come to rest in stillness and in its own natural clarity in the present moment.
  [17:23] Now cultivate this ability of letting your awareness rest in its own place, holding its own ground, which means not directing your attention to anything, neither to any sensory impression nor to thoughts, images, other mental activities or even to the space of the mind, no directionality, no target. Just let your awareness rest in its own nature without meditating on anything, without doing anything. Simply being present.
  [18:42] Sustain this flow of present centered mindfulness, a mindful presence without distraction, without being carried away, without letting your awareness be set into motion obsessively. Sustain the flow of mindful presence without distraction and without grasping, without latching onto any object, either subjective or objective. Simply be present. Whatever thoughts come up just let them be without perpetuating them or grasping onto them, without following them. Simply let them dissolve of their own accord back into the space of the mind.
  [21:06] And now within this context explicitly be aware of something you are probably already implicitly aware of and that is namely the rhythm of the breath. Without explicitly directing your attention to the sensations of the breath throughout the body simply continue to rest your awareness in its own state. Within that simple presence, awareness resting in its own place, take note of the duration of each in breath, each out breath, whether it is long or short. And let’s continue practicing in silence."


So this is how I am viewing it. I am combining awareness (mindfulness of my thoughts with introspection) with mindfulness of the duration of in/out breaths. When thoughts arise, they are mindfully observed, but not viewed as an interruption of mindfulness of breathing. When no thoughts are in mind, focus shifts to the mindfulness of breathing.

So it seems to me a like a very flexible model. No preference is given to mindfulness of thoughts or of breathing. Rather, the instruction seems to be just be mindful of either one, depending on the random rise and fall of thoughts. Mindfulness of breathing seems like a place-holder for attention when no thoughts are in mind.

Is this right?
I am combining awareness (mindfulness of my thoughts with introspection) with mindfulness of the duration of in/out breaths. 


This is right. Anapanasati Sutta mentions about discerning long or short breaths as the 2nd step in the 1st triad.


  When thoughts arise, they are mindfully observed, but not viewed as an interruption of mindfulness of breathing.


Realising that thoughts arisen itself sometimes bring you mind back. If not 1st be aware of the through and breath. Then look for any sensation that the thoughts might have brought, e.g. discomfort if they were angry thoughts. Finally actively redirect you mind to the chosen object.


  When no thoughts are in mind, focus shifts to the mindfulness of breathing.


Initially you have to keep brining back you mind to the breath even if it does not wander away.


  Mindfulness of breathing seems like a place-holder for attention when no thoughts are in mind.


This is how some meditation master teach this, but thinking and pondering is verbal fabrication which need also be calmed. [Samma,ditthi Sutta]

Also the following might be of interest: Anapanasati: Mindfulness with Breathing - Unveiling the Secrets of Life by Ven Buddhadasa Bhikkhu