There are many articles on the internet about the speakers stands (use Google). There is also the litrerature dealing with this subject, for example Jim Smith: Get Better Sound. However, the stands must be rigid and must damp the vibrations as much as possible. Considering the height of the stands, there is "golden rule" - the tweeters should be as high as the the listener ears. I think, the placement of your Kefs on stands would be better solution.
Impact of speaker stands?
OK, I recently acquired Kef R300 speakers to go along with my Ohm Walsh 2-100s. I presently have them sitting on top of 2 JBL L110s as my "stands" as the JBLS are not being used. The JBLs are 24 inches high...the same height as the stands I would need based on the KEF directions for placement. The JBLs sit on the wood floor on top of foam pads. The Kefs sit on foam pads on top of the JBLs. I have never had speakers on stands. The question is, what if any, benefit would I get from buying real stands? I think these would cost about $350 for good ones shipped to HI.