I installed on my system some commercial PostScript fonts. For all of them, metrics were available on CTAN, namely in the Schmidt's collection http://www.ctan.org/pkg/w-a-schmidt.
Now, most of the metrics were created a long time ago (about 2004), and most of them (according to the attached documentation) seems to need some revision, which was never implemented. Since their release, some updates to fontinst have occurred (the last in 2009), and version 1.9 is very well documented (see, e.g., http://www.ctan.org/tex-archive/info/Type1fonts/fontinstallationguide/).
I was wondering what are (if any) the additional qualities of the CTAN's metrics as opposed to the metrics one could quite easily generate following closely the Font Installation Guide cited above.
To be more concrete, consider for instance Tutorial 6 of the guide, where metrics for Minion (with Expert subset) are genereted. How do these compare to the ones provided by the pmn package from w-a-schmidt?
I guess that they probably "look and feel" the same, but I suspect that there are some (small?) typographical differences that a trained eye (maybe not mine) can notice.
In other words, do the metrics provided on CTAN contain some tricks that the most recent fontinst cannot reproduce easily?
Of course, I know that for those who use LuaLaTeX and XeLaTeX most of this discussion seems useless. Nonetheless, I still prefer to use the "genuine" LaTeX (for a number of personal reasons).
I am mostly interested in precise and technical answers. Thank you in advance!