None. If they come up naturally we go with them. But we do not consciously practice any mudra or bandhas during meditation.
http://www.aypsite.org/55.html During meditation, we don't deliberately do any of the practices we are doing in pranayama. If we find ourselves in mulabandha in meditation, we don't favor it or push it out. We just easily come back to the mantra. We want to keep our meditation as simple and pure as possible – just that simple procedure of using the mantra. You may notice a change in experiences in meditation as more ecstatic energy is naturally flowing through the body after pranayama. Ecstasy is just one more thing that can be happening during meditation, like thoughts, feelings and physical sensations. We just easily favor the mantra, let it refine and disappear over and over again. This will make the rising sexual essences all the more pleasurable in the subtle nervous system. Meditation will be all the more effective as pure bliss consciousness rises, and permeates and expands inside the ecstatic energies coursing through the nervous system. Extraordinary joy!
If you learn the practices from the Secrets of Wilder novel (as I did) then you will at some point be deliberately bringing mudras and bandhas into your meditation practice (as well as siddhasana). This is only done when you reach the point where the extra energy dynamics do not effect your meditation practice.
The proviso about not being disturbed by the energy doesn't apply to Spinal Breathing Pranayama, so you begin by adding mudras and bandhas only to that practice at first.