Standmount speakers - alternatives to spikes?

Why don't you just used floor protector disks or even pennies under the spikes?

Better results will be had if you treat the equipment that resides in the rack first and keep the rack coupled to the floor using the spikes. Just make sure that the rack's spikes have the weight equally distribed thus avoiding any wobbling etc. Also, if you can position your stand as to have the feet as close to the floor joist as possible, the better.

Sorry, I thought you were referring to the equipment stand. For speakers stands, my feeling are the same, couple the stands and decpouple the speakers to the stands.