Hello. I am planning to move my fence out to the retaining wall at the property line. A company asked if I wanted it on top of the retaining wall or inside the lawn. Spontaneously, I think it would be cheaper and more stable to place it inside on the lawn, but maybe that's wrong? The wall stones are not mortared but rather laid on top of each other. Will it be stable to drill into them and place the posts on top of the wall? Estimated price difference? Anything else to consider? I won't have a solid fence like today but narrow gaps between wide boards. Probably also horizontal boards.
I would place it inside the wall. Even if you build a fence with gaps, it will become a huge wind catcher, so at the first autumn storm the fence will topple and take the poor stones with it in the fall. Cast deep plinths to secure the fence so it will stand straight and steady for as long as you wish.