3. Using \chardef\characteralignmentmode=2 widens columns and doesn't quite center the data.  It appears as if the decimal is centered, but this does not necessarily center the text.  The top row shows tables without setting the alignment mode, the second row of tables show what happens when it is set equal to 2.  It would be nice if the left-hand tables looked the same, and the bottom right were centered better.  test3.tex demonstrates this.