FWIW, spikes/cones do not isolate speakers from wood floors. They are very efficient at coupling your speakers to the floor. If you want to isolate you need something which is inefficient at conducting the frequencies you want to block. Nothing is perfect, but I use cheapo hock pucks. Hard rubber. Passes few vibrations that will effect the sound of your speakers than metal.
If you want to use the spikes get substantial metal cups. Years ago I tried spikes on coins with heavy speakers. Pierced the coins and damaged the floors.
If you want to use the spikes get substantial metal cups. Years ago I tried spikes on coins with heavy speakers. Pierced the coins and damaged the floors.