Matched Set...
I was being a little facitious, and I apologize for making that comment without explanation...
I too had to adapt 4 Pioneer speakers, and two separate pairs of stands when I first started 15 years ago... one set of stands fit better than the other set... but I didn't have the problem of speaker movement that you are experiencing... maybe my setup wasn't as powerfull as what you have now... I now use a Bose PAS System with superb results, so my Pioneers with stands have been in the storage locker for the last 6 or 7 yrs!
Hope you find a solution, without going to the expense of matching to expensive adaptors!
Rick