I'm confused about your question. We know what kinds of hands he flats with and we know his flatting range is really wide. Knowing exactly what his flatting % is is kind of useless as it's much easier to assign villain a range when we know which cards he's flatting with. Saying I think he has a 30% calling range is not putting him on a range.
If you know his playback (4bet?) why don't you know his other stats?