I would suggest that you set up your high rates at 100% attempting to use geometry of the linkages to attain desired throws and then use the computer to make up for mechanical deficiencies that just can't be otherwise worked out. Then set low rates wherever you choose at a point below that.

You really don't get much more throw with those last few degrees of servo wheel turn if you really study it closely. Most of your throw per degree of rotation is near the neutral point.