tigers650.
Expo is usually a person preference bast on one flying skill and feel. However. Here is what I do. I set up the low rates on the Venus II as suggested with -15% on the Ailerons, 20% on the rudder and elevator. I like a little softer stick center for landings and take-offs. My Mid-rates are a little more throw with very little Expo, 10%, for pattern flying. The same for high rates, which I rarely use??, with no expo.
I have played with Low and Mid rates depending on the maneuver. Example I want very little aileron throw for slow rolls. I use higher rudder throws for deadhead stalls. Softer rudder throws so corrections aren't noticeable
I guess the best is to use more expo as you learn the Venus II then adjust as you go.