I recently sent a note to the QST technical correspondence editor at the ARRL concerning the effect of radial system asymmetries in elevated radial systems. You can read this letter at: Download December 2010 letter to QST technical correspondence . This note emphasizes some of the problems with elevated systems and some possible misinterpretation of my March 2010 QST article.
After sending this note I realized that there was a lot more to say on the subject. So I'm in the process of writing a very extensive article on elevated wire ground systems and the effects and cures for asymmetries. That is however, still couple of months away from being finished. I will post it here when it's done.
73, Rudy N6LF