Try The Cable Co. They're a lot bigger and more knowledgeable. And much better to deal with. They'll send you all those cones first so that you can try them in your system. There's no better way to do it.
Isolation disc for speaker spikes on wood floors.
Just did a little search, and it goes from pretty reasonable to quite expensive. Isoclean prices them as sets of 4, while others like Black Diamond and Symposium each. The BDR's are $30 each, but I need 8, so these things aren't cheap. The Isoclean's are $160/4, so they would run over $300. My sources are Music Direct, and Acoustic Sounds so far.