Although I agree I think the medium plate would be great for the tinymight, being that I only have the fun plate myself right now I have to say that it works great as well!
I only get a really fine grind if I grind upside down with it, if I just load and grind normally, I can get a pretty nice consistent medium fine grind that works very well in the tinymight.
However I bet the medium plate will also give you a very fine grind if you grind upside down, and if using it regularly you'll probably get a more coarse grind, so yeah I think it's a good choice!
I just ordered an entire second BCG with the medium plate myself, so yeah you can't go wrong with either and one may leave you wanting the other eventually (I got my first one last year during the 420 sale) not to mention the colors!