Unless I am missing something, why would you bother inverting the Jack? Surely you could make the jack upright as the force is the same at the top as the bottom, put the jack on a movable plate with a solid round bar underneath on the bottom of it to do the work, as the ram extends the jack, the plate with the round bar moves up and down against the work holding the jack in the proper position. I could never understand why people do it this way!