[Fontconfig] Still Baffled

[John Lowell]

I must confess, after having written here earlier and not having gotten 
a reply and having done much additional research since without making 
much headway, I remain baffled respecting different font behavior using 
fontconfig in two distros. Let me restate the problem, perhaps someone 
can provide light at this point.

I'm trying to understand why it is that using Gentoo and 
gtk-theme-switch (which relies on fontconfig to change fonts and themes 
in various applications) I'm offered a different font selection than 
that offered in Debian or Arch using the very same program. Configuring 
/etc/fonts/local.conf to identify a special font directory in each case 
(/usr/local/share/fonts in Debian and /usr/share/fonts in Gentoo and 
Arch) and copying identical font directories from 
/usr/X11R6/lib/X11/fonts into these directories, gtk-theme-switch offers 
entirely different font interpretations in each case. For example, 
lucida regular is shown in gtk-theme-switch as an option in Debian but 
when it's selected, lucida semi-bold is the one actually offered. With 
Gentoo, the same selection yields lucida regular, medium weight. Why 
would it be that there is a difference here? One would think that lucida 
regular means lucida regular. I'd really appreciate some help with this 
question. I mean if I can't get it here, where can help be obtained?

John Lowell