Speaker Spike Bases

I have SF Olympica llls on tile floors with the original spikes setting in round metal bases with either a very thin rubber or felt pad under the base. 
Should I try thicker rubber bases on the ends of these spikes because they are sitting on tile floors? 
Would this improve the bass or overall sound quality?

If recommended to try a rubber base, would hard or softer rubber be better. Can anyone recommend a source?

Thanks for the feedback.