Having been intrigued by the nice glyph width chart on the Neue Haas Grotesk page, I could think of no better way to spend half this holiday than to write a Python script that will plot a glyph width histogram.
The results are, not surprising, that different digitizations differ wildly in their glyph unit systems.
Here are some examples:
The Linotype Stempel Garamond is based on a rough 18 unit grid.
URW Garamond No. 8 has something like 3 times 18 units, 54 units.
The Berthold digitization of Stempel Garamond uses a completely incompatible grid, i.e. 48 units.
The same grids can be seen in the attached PDFs of different Univers digitizations.
If anyone is interested, I may clean up the Python script and make it available.