The size of the font, as well as its boldness and apparent color, are dependent on exposure and cropping–and this, I learned, is not consistent from film to film, nor is it even consistent from subtitle to subtitle within the same film. For example, if the subtitle was added, but then the frame was slightly cropped, that would effectively make that subtitle larger and bolder than a subtitle added to a frame that was not cropped. Similarly, the position of the subtitles within the frame could move.
The fonts I came up with were for a specific purpose–to blend when shown in sequence, but not necessarily to be identical side-by-side. They aren’t designed to be authoritative, and they don’t exactly match any subtitle–they’re more like the median representative subtitle.
IIRC, of the fonts I made, Star Wars is boldest, Jedi is less bold, and you could grab the German ROTJ font for what’s probably the least bold of them all. But they are all the same font, with variations in exposure, etc.
Keep in mind that the graphical SUP files for the alien subtitles are based on actual 35mm prints, not from the font files. While the images for Jedi were made by Harmy (who is skilled in such things), the ones for Star Wars were made by me, and have some flaws. Specifically, each individual subtitle should have some color variation within it, the ones for Star Wars don’t have much. This probably gives them more of a clipped, flat feeling (maybe could be interpreted as boldness) that you don’t see in the Jedi ones. Nevertheless they do have all the variation in size, boldness, and even variable letter forms and letter spacing that you can see in the films.
If you want to use the actual subtitles from the films, use the SUP files. They are much better, albeit not flawless (well, maybe the SUP files for Jedi are…). If you want to use the fonts, well, they’re honestly probably good enough for your purposes, and I’m not looking to improve them because they’re good enough for mine.