It is NOT Necessary to have a switch assigned prior to teaching the (Programming) the gyro your radio setup.
"With 40% ATV, what gyro gain does that correspond to?" You need to look at your servo monitor to see the actual output, at 40% ATV, I see an output of 83 on my servo monitor.
If you want to set up the other side "off" switch position to a lower gain, what would be a good starting ATV? 20%, BUT I suggest you use the the Demon software and set Bank 2 to Rate mode first!
FYI, I'm putting one in my big Futura and trying to decide if I should use the built in Gyro feature on my 12X or this "easy" method. I did not could not get the Gyro feature on the JR to work the same as Futaba.
Craig IF you are 100% comfortable with setting up the Cortex go with Harley's settings. I suggest if you are doing this on your own you have a way to turn the Gyro on/off "Just in Case" for those first flights
I sent you a PM with contact info.
Bob