I have no preference that I wish to place out there as it will depend on floor type, construction, and also walls believe it or not. I still don't fully understand as when I think I have got it an exception happen. One was a couple of wobbly three legged stools (you still see them in some of my old pics) I found in a charity shop for fiver, they worked well up stairs in my work room in Epping with a ply wood floor laid over beams, down stairs on the float concrete floor they didn't. Here in Sidcup they didn't work anywhere so they went on the fire. One of the best things on a concrete float was a pile of bricks. I also mention walls as modern houses are board, and they rattle if the energy gets to them, which it will with suspended floor, bricks wont move and breeze about the same, and obviously concrete floats don't move.
Overall I favour mass, as much as possible, as that can even overcome suspended floor problems, and remember the bigger the drive unit the more energy is moving. So look at it yourself and explore the options as it is not *just* stand, the stand has to work with the floor and the room as well as the speaker.
Cheap solution, just get a pile of bricks
on a large heavy paving stone underneath and smaller one on top.
Did you get them Doc?