I use Nobsound springs under the existing feet. But, only way to be sure on your system is to try.
Four Nobsprings are plenty for 40 pounds. I would remove enough springs for them to compress about half way when loaded.
If I chose to use a cutting board, it would be under the springs and separated from the shelf by vibripods or other elastomer disks. This gives another layer of isolation. I am doing something like this using a Black Diamond Racing platform and springs on top and vibrapods under. I would not couple all the springs together… and most components are heavier in back. Best to tune the springs to each location.