re: Do you use leveling feet?

You usually only have to adjust one of the feet to eliminate rocking. In Ron's example, it looks like he has just one leveler and that may be all that is needed, unless the floor is really unlevel.  It is not really supporting that much weight so those side mounted levelers might be a good idea for ease of use, if you frequently move it around and have to adjust it every time you do.  Same thing with Carey's example.  Sliding a wedge under one of the legs will usually stop the wobbling.  Sugar packets or folded paper napkins always work on restaurant tables.   😀