Quatro Wood best feet


What is best isolation fee for Quatro Wood speaker other than stock spike, maybe not granite either since I have stone tile, and concrete underneath. any advise will be appreciated!

Best Regards
Zee 
zensview
2". rut roh...did I order the wrong thickness.  I better find out tonight and change if it's not too late.  wow. thanks.

@tomic601 I  I did matched impedance for M5 high pass output, and my tube amp input, I do have a Meterk Digital Sound Level Meter, should I better stay with Radio Shack Analog SPL meter for Quatro wood setup? I have to look for one!
Zee
yes you need the RS Analog , the Vandertones are calibrated to that
it should be $30-$40 on ebay