So, not quite ready for prime time, I think. Cool idea, though.
Tifinagh letter tuareg yazh: ⵌ
Vai syllable pu: ꖛ
Equal and parallel to: ⋕
Viewdata square: ⌗
Both were successful, and put the desired character at the top of the list. All the others worked first time.
It would be excellent if it could be made to learn, with users being able to say "that's what I meant"