It all depend.
Naruto loses conciousness at three tails, while Yugito is still in control, even in bijuu mode.
If it was 3 or 4 tails would be Kyuubi fighting like Kyuubi stated.
So i guess it would be fair if it is Naruto at two tails (which he barely can control according to Jiraiya) againts Yugito with two tails.
Fraid not. As I have it it goes more like this:
Kyuubi Chakra - Normal
1 Tail - Naruto control
2 Tails - Naruto control, Kage Bunshins feel pain
3 Tails - Naruto control, but barely
4 Tails - Naruto KO'd, Kyuubi control