If I can make a suggestion? There are quite a few free woff icon font sets out there which are considered open and free, but selecting from them to create a tiny reduced set is SO (blankety-blank-insert-cuss-word-here) difficult that most of the time we give up and either go to a different set or use the whole ding dangy. Trouble being I am developing a “portal app” where the size constraints (to fit comfortably and quickly even on the smallest platform (A Raspberry Pi-Zero w) and run quickly mean “absolutely minimize the woff size”.
Anyway, my thought is that if a user (even paid works on this one) can upload their woff sets with a json listing of “I want these fonts from free set XX, XY, XZ” call my reduced set YY, and include the licenses/cc notifications in a list"… and have your converter make the set using the json listing, that would be “world useful”. Thoughts?