Weights on top of equipment to dampen vibration

It depends on everything. Your component and its case, what is under it, the metal of the case, the material of the weight, its location on the component, how it couples with the component, what the component is sitting on, what your flooring is like, where the component is relative to the speakers, how loud you play, what standing waves you have in your room, the positioning of the wires and circuit boards in the component, whether there are mechanical or ac induced vibrations in the unit, and your tastes all matter.

Trial and error is your only alternative. There is no reason to think that anyone's experiences here transfer to you and your system.

Musicfile, look at it as an adventure. Whatever you try experiment with many locations. This is true also for feet under the components.