We don't have a lot of stats yet, but I'm at 1700 characters after 60 hours of practice, and I probably could only write 600 when I started.
The Supermemo technique should be good at keeping the pace up to get to that magic 6000 character level. Once you get a lot more data I would think you would have something worth publishing in journals of education and that could be a very nice PR opportunity for you, showing that your software dramatically improves the time needed to become fluent in Chinese.
6000 characters is very extreme. I think 3000 is a more magic target.
I expect we can produce some very sexy stats, once we build a data analysis framework for it. Do you think we could publish just based on our online practice data, without doing a more traditional study?
As for publication, I'm really not sure. I think it would depend on you finding someone else's data for Chinese language learning for comparison purposes. There's probably some conference somewhere you can present at, if nothing else.