Spikes are not about solid floors - on solid floors, spikes are more likely to make things worse, by reducing stability.
With TT's the idea is to isolate the TT from environmental vibrations, just like your car's suspension isolates the passengers from the road surface. hence you use shock absorbers when you can't solve the problem statically (e.g. wall mount the TT). The Oehlbach Shock Absorber is such a device.
With speakers the idea is to couple the speaker to the floor so that the speaker does not rock as a result of the movements of its own cones. Obviously the best solution would be to bolt the speakers to the floor, but few people like to do this. The Oehlbach Shock Absorber does exactly the opposite of what you want to do when applied to a speaker - it is designed to increase the speaker's rocking. For speakers you would want an Oehlbach Spike, not one of their resonance dampers, assuming that is that you needed anything.
There is an exception - when you have a bookshelf speaker on a shelf that also holds a TT, for example. In such a case want to keep the speaker's vibrations from affecting the shelf and hence the TT and would use a shock absorber to protect the shelf. The sound is already compromised, so it won't get worse.
Spikes are used when you have a layer of (spongy) carpet or the like between the speaker, which needs to be kept rigid and immobile, and the floor, which is already rigid and immobile. The spikes pierce the carpet, allowing the speaker to rest on the concrete floor.
The problem with (suspended) wooden floors is that the wood is elastic, so is not immobile. For such situations, heavy concrete slabs can be used to reduce their elasticity. In your case however, "they are not an option".
