For females, and I speak from experience because I own the canine line and I happen to BE female, I'd suggest the Durka.

The shaft isn't so long that you can't knot it and its knot is nice but not TOO big either.

I know for me, I have issues with toys being too long that I can't knot them, due to our inability to take as much length as men...but the Durka works really great for me. It's the perfect length and the knot is just fantastic.