Good question !
And thanks for the links, it is very useful !
It would be nice to reach those schemes more easily, in the software. Letter like J or F are really confusing, since it is not the actual signs we draw.
Also, I believe the way we write some letters is different from country to country, English speaking people don't write a J as the Frenchs or Germans do.
so I am not sure the "block printings" letters are a good reference to show in the gesture list.