[kizza42]

The unfortunate thing with the DX6i is that while it has the options, the visualization of the options is terrible.

What you have there is:
No dual rates set up on any control throws
100% end to end throw on all Servo's
60% Expo on the Aileron and Elevator which is a gradual curve of less travel in the centre regions of the sticks out to full movement at the extreme regions

Pretty much all these options come down to personal preference.

There are 2 schools of thought to go with:
Darren will suggest absolutely no exponential control (meaning full linear control of the control surfaces) but reducing the amount the servo moves to be only what is necessary to fly the plane. Roll servo's for example may only require 40% of normal throw to give a controllable roll rate. Elevators might only need 60%

Kieran will suggest having 100% control surface movement available for maximum turn and burn action and extreme situations. To counteract what would be a very twitchy plane I put large amounts of exponential to dull the movements in the centre regions of the control stick.

Nothing stopping you having a combination of both!
Horses for courses...