Small ball bearings or small pea size stones work best, fill them to the top as you want them to be dampened as much as possible. I then use some poster board putty formed into small golf ball size then pressed hard between the speaker and stand this couples the two nicely.
How much lead and silica sand in speaker stands?
Is there a right amount of lead or sand in speaker stands? Do I fill them all the way to the top? Fill 1/2 way? Certain inert materials better than others? Do different materials effect the sound quality differently? Any esoteric comments appreciated!