Like Paul said, I don't follow the suggestions about studs, sheetrock, wallboards, mollies etc.... because we build our houses and walls completely different than in the US.
I used my own plugs and screws (check the picture above) and not the plastic ones Stringswing delivered. I don't think it is necessary to reinforce our walls with some extra things like wood etc. The walls inside the house are made of thick red bricks of approximately 10-inch depth! On both sides of the walls, we place a kind of white primarily decoration material like you see on the pictures (Paul help me with this, how do you say bezetten? or ?plakken in English?). We normally paint or decorate with paper straight on that white material. The plugs fit into the brick real nice. When you put the screws in, the plugs open a little bit further, so they can't move anywhere without breaking the brick which is way to strong.
Don?t bother about earthquakes here in Belgium. In my entire live, I never experienced one, but I can imagine our US friends think completely different about this.
I?ve just checked the collection: after 48 hours they are doing fine. I feel more relaxed now
Cheers
Jan