I used generic bluetack on my B&W805s stands.
I made it super thin by kneading it with my fingers until them bled!
1/32 inch thick (any thinner and it 'tears')
The sound without, and screwed to base was too 'tight' in the bass and a bit bass shy.
With the bluetack substitute the bass came out just enough to be perfect!
The generic worked for me... just remember to knead it a LOT before using it. The more the better.. (keep pulling it in to a long strip then fold, repeat. after a dozen strech and folds, twist it up about 30 twists, real tight. then repeat streching and folding. then roll it up into a ball or tube and use it anyway you want.
Makes the stuff much much better.