Yeah, band-balancing is Ruckus's newer implementation of band steering. Instead of blindly directing everyone onto 5GHz, it attempts to be smarter about maintaining a certain load balance between 2.4 and 5GHz.
I think you are correct in that by default it takes until 5 or 10 client associations before it starts, and on Standalone/ZD there are rpmkey hidden knobs that allow you to tune its specific behavior... I'm not sure if those same options are available on Unleashed though -- Unleashed seems to have a very different CLI implementation.
But are you sure this is what you want? Personally I've had less than perfect luck with band steering, and that's not just with Ruckus. A lot of clients are very stubborn in wanting to connect to a particular BSSID it thought it knew about (such as the 2.4GHz one) and band steering merely adds a delay to connecting, or if set too aggressively causes the client to give up on your SSID altogether.