I am a firm believer in spikes especially for heavy speakers. At the very least they compensate for uneven floors. If the speaker has the potential to move so does the image.
I make these out of lead. Lead does not resonate, period. I can make them with 1/4 – 20 or 3/8-16 or I can make them as a nut to accept a bolt or rod. Because they are poured they are a little rough but when I sand them and paint them they look pretty good and work great. A friend of mine said they improved the sound of his Music Hall TT.
I think Mapleshade has a good product but 40 bucks a piece is still pricey for us DIY guys. It takes me about three hours to pour, clean up and paint a set of 8. With SS bolts and paint, I think $80 for 8 is fair. Even if you don’t want these it gives you an idea of what can be done with some thought.