I am not convinced. They are not a torsion bar, they are designed to stop fore and aft, side to side, and up and down movement, not resist rotational movement. After all they get greased to prevent squeaks, and squeaks are from movement around them rather than twisting.ALSO, the arm should be held at normal working height before the nuts and bolts are tightened back up. This is so there is no twist in the bushes when in working conditions.
Tony.
Mine started squeaking even though the grease was used. A couple of squirts with 3 in 1 and the squeak has gone.