i can recommend the bronze bush mod my dad made me some .50 years ago ,also a mod in the day was to fit ,tramp rods ,two lengths of flat steel attached to a bush located by a ring clamp on the axle tube ,then located at the rear chassis rail ,just in front of the engine mounting cross member ,attached with a bolt going up through the chassis ,the longer these flat steel bars the less they are going to affect the front to rear location of the swing axle .i remember having my head out the window of my 54 4cv when reversing ,and seeing clearly how much the rear wheel moved when backing up an incline ,when you consider the distance between the trunnions compared to the length of the axle tube ,there is a lot of leverage there ,a little movement at the trunnions represents a lot more at the wheel .pugs