I thought Phil had ruled on this on the Yahoo site?
From my remembrance of this I believe that you move the first element, which becomes the head of the column, the maximum distance it can move, the other elements then falling in behind making their maximum move distance. Any element that cannot fall behind because the distance is too great then is moved sideways and placed by the side of the column. The next bound is the tricky one as if the column remains in a column when it moves, the elements on the side then either move sidewards and forwards as the column advances, probably leading to the rear most elements not moving, or waiting until the end of the column allows them to tag on behind.
Also Phil said that as long as the head of the column moves the full distance it can, including any wheels etc, then that counts for the 'both corners moving full distance' ruling.