[TJ Mason]

Inside/belly/facing you, I'd say for the mushroom-shaped ones, because that way the cap of the mushroom is pushed into the stem when the bow comes to a stop. If they were on the other side, the cap would be pulling away from the stem. Putting them on the belly should thus prolong the life of the limb savers. I doubt that it makes a difference to how well they dampen vibration.