My supports are not rigid - they are designed to wobble in the horizontal plane.

In the vertical plane they are rigid, however,  and coupling works from each component on each shelf downwards to the floor, decoupled from each other shelf along the way.

Low resonance from each shelf (wooden and non ferrous i.e: non -ringing) and the rods (aluminium and not ringing at critical HF frequencies) between them also seems to help. It works in my system.

The ultimate coupling system is Mana - and it works also - if your system is in dire need of it/you like the (resonant) effect TM. (imho)

I know of at least one system that  needs  Mana to work effectively. Mine doesn't.