The Hover value is in your logs when you switch to Alt Hold. You should see it with the mode switch name. Mine was 495 which is the equivalent of 49.5% throttle. A lower value has a profound effect on the flight so play around with that.
The A copter is the current control solution. The B and C copters are Pi->Pi rate based solutions and are identical. You can adjust PID setting to pit the two against each other.
The scale on the left is meters. The Sonar is active and the mix is identical to the current AC2 solution.
This new code is in testing and will be available next week in 2.0.40b