On the same lines, if you plan to setup dual rates, it's easy. And computer radios are excellent at it.

You've already rigged the airplane's throws as above so the airplane is giving the best of what it's got to give. As described above. So........

Set the high rates at 100%. Airplane and dual rate switch good to go for high rates.
Set the low rates at whatever you want, like 70%.

You got dual rates and at the best settings for the battery in the airplane and all the servos that're going to be called on for those dual rates. Especially when set to high rates.

Same reasons as above.

And later on, if the high rates don't seem high enough.... what to do????? Simple. Work on the rigging in the airplane to give you more throw. Same reasons as above.