Im using a HH gyro on my Pro with the 3 in 1. All you do is turn the proportional all the way down and the gain can stay where it is. The HH gyro will over ride th gyro in the 3 in 1. Its a lot easier going this way I would think.

I think drphoto is right. Im not sure that you can run a lipo on that 2 in 1. You need a lipo compatable ESC for a lipo battery.