if you're actually serious about your venue, don't go for all these kitchen solutions
What you need is Maglev. It's basically two plates being positioned by magnets (so no direct contact at all) and so there's no feedback or nothing. They also come in big variations where you can place an entire setup on those things, making the entire booth absolutely stable and feedback-proof. We use it everywhere, even on wooden stages etc where normally you'd be bouncing around the place from the bass in the floor.
Works perfect, the only thing you can't do is place a laptop directly on them since that can be a little dicey for your harddisk
![Smile :)](./images/smilies/icon_smile.gif)