Blu-tack is the best medium to couple speakers to stand. Four small, very small (3mm) pea size, one in each corner 10mm in, position speaker, press HARD down, the Blu-tack will spread to a large paper thin contact area, think suction pad? Years of experimenting has showed this to be the best setup. To remove speaker, twist through its vertical axis, try to pull using the cabinet as a leaver risks tearing the venerre!
As has been mentioned, patialy filled stands work best, trial and error is the only way to establish the best fill, 1/2 to 3/4 full is a good starting point?
There is a lot of missunderstanding regarding floor spikes, originaly conceived by John Michell as a means for a solid standing through the then popular, thick underley/fitted carpet in homes. Works great all that weight on to a tiny point! Problem is the energy in the stand does not transfer into the floor very well . . . think about it, fill a bowl with water, water represents 'energy', drill a 1mm hole in the botton of the bowl, takes for ever to empty. Same senario, bowl/water, drill a 6mm or even 10mm hole, the emptying process is very quick, 'better transfer of energy'? Still not that quick but you get the point.
Spikes are nothihg more than adjustable feet that will damage modern wooden floors. Blunted spikes into cups is the answer for wooden floors, giving the speaker an 'adjustable, solid, rock free standing'. The work of dispersing energy has to be done by and in the stand, filling and patient listening tests required.
Material for filling, there are expensive, commercial offereings, they can work but dried sand seems to do the job OK, dried sand used for block paving gap in-fill is good and cheap.
CJSF