I have updated my Refont program, to now have a function that can analyze a font DAT file for missing or problematic characters. As part of a broader inquiry, I've just applied that program, individually, to all current 'english' font DAT files. I'm reporting the overall results here. I'm sure this will not be a surprise to some of you, but may be to others.
Background
As you know, TDM fonts are based a bitmap system, derived from 256-character code pages, of which "English" and "Russian" are currently supported. "English" is actually Latin-1, with additional characters to cover more European languages in a single codepage. This is (in theory) quite good for major European languages, less so for less-prominent ones. For each font, bitmaps are distributed in 3 sizes (12, 24, 48 pt), with the engine doing interpolation scaling.
Current Font Findings
12-pt Size for All Fonts
Only ASCII (i.e., lower range 0-127) characters are provided, no European. For some fonts (stone, mason, mason_glow), the 12-pt DAT is not distributed, so the engine will substitute a larger size, which typically has better Latin-1 coverage.
For Fonts Used in Main Menus, HUD, or Subtitles
The numbers shown approximate the number of "characters needing work"
Fontname Size-24 Size-48
carleton 20 16
carleton_condensed 20 35
mason -- 33 Since 24 pt is not distributed, engine uses 48 pt.
stone 30 83
For Additional Fonts Used in FM Readables, Etc.
Except for one font (treasure_map), all the remaining fonts are ASCII-only, i.e., no characters in the upper range. In the lower range, routinely the 24 and 48 pt sizes have equivalent coverage. Most of these fonts are fully or nearly complete, while some neglect certain punctuation symbols. The worst is "everette", with 24 "needing work" characters.
Further details are here: