The thing is, if my font is Romans.SHX and I want one of these unicode characters, then 9/10 times the charcter is displayed as some TTF font (usually Arial). If I set the Romans to use Big Font, then most of these characters display correctly. So it seems that BF simply implements the UniCode in the font as well, meaning instead of only 230 od characters there could be 1000's
I've not tried the Standard.SHX much. We generally don't use it. So I can't say much about its Big Font, though I think it uses the same one as for Romans.