I followed Dave's direction and used Museum wax under Sierra-1's and 200SE's. I used large amount of wax and used isolation feet to ensure the speaker was not contacting the stand as I squished it in place (probably not needed). 2 years later I tried to remove the 200SEs to place on bookshelves and had to cut away alot of the wax with a plastic knife before I could even move the speakers at all. I think with museum wax for sure the speaker and stand will be well bonded. It was also very easy to remove museum wax from the speaker cabinet.
My biggest fear (with 2 little kids) is whether the speaker stand itself can be knocked over on hardwood flooring. Though I've sand filled, the little brass spikes in plastic cups look nice, but do not inspire my confidence. I don't know if anyone's tried museum wax under the speaker stands (instead of the brass spikes), but I'm tempted to try it and place the brass knobs cosmetically on top.