Intolerable difference in glyph width: font=vnbx12

[Karl Berry]

As Reinhard says, side bearing information (hsbw) is not present in
pl/tfm files, because side bearings are about where the glyph sits in
the box.  As we all know, pl/tfm are solely about the metrics
(height/width/depth/italic_correction box dimensions, kerns, ligatures),
and nothing at all about glyph shapes or positions.

In order to find the canonical "hsbw" for Metafont fonts it would be
necessary to look at a high-resolution gf/pk file. -k