The type of coupling for any kind of speaker to the floor is a matter of system tuning. In other words, there is no one right way to do it; one must experiment to see what works best.
A lot of times spiking a speaker to the floor is not the best approach, even though the manufacturer supplies spikes for that purpose. On suspended wooden floors, effective coupling of the speaker to the floor might mean that the floor itself becomes a big sounding board which muddles up the sound, particularly the bass.
I would try different approaches. Keep in mind that if you change types of spikes, etc., you will need to make necessary adjustments to get the speaker height and rake (how much it is angled backwards) adjusted.
With my floor standing speakers, the use of a big energy absorbing platform, with the speaker sitting flat on the platform (entire bottom in contact with the platform -- no spikes) worked the best. The platform I used is a big Symposium Svelte Shelf. This consists of two aluminum outer panels sandwiching a foam core (vibration is converted to heat from friction in the foam core). This approach effectively dampened the speaker cabinet itself and prevented energy from feeding into the floor. But, in other setups, this might make a system sound too dry. Experimentation is the key to any tuning of a system.
