The use of dual rates / expo is totally dependent on your preference.

I don't use expo on any plane while I'm flying 3D maneuvers, and on most I don't even setup dual rates to use in "normal" flight. Even with setups that use more than 45 degree deflection each way.
The expo IMO make the controls slugish and not very usefull for 3D. Again though thats up to you and what you like.

Bill