I have 2 computers on the same IP (yes it is a risk you should avoid if possible) running HummingBird 2.0.240. Each of them is working on about 5-10 accounts at a time, and I replace a new account once it gets to have about a thousand followers. I have been doing this for months so it shouldn't be a problem running multiple accounts.
The only thing that's annoying me using HB2 is its capability to unfollow. It is simply unpredictable. I have a few accounts with only 300-500 followers and HB2 keep following new people nonstop (ie. no unfollow) until it reaches Twitter's first cap at 2000. At first I though those accounts would have been killed by Twitter soon. But somehow they lived on and graduated by growing into a thousand followers.
You can't say the unfollow function is not working. Because it happens on some accounts. I just have no idea on its working logic, surely it is not on the way its user manual has said.