The CVT will automatically figure out optimum engine configuration based on you current speed and the position of the gas petal. I have not observed any "sweet spots" with respect to speed, engine RPM, etc. The car does a lot of that. I manage my daily drive by watching the real-time MPG display. I think there are "sweet spots" relative to that guage.

When I accellerate, I try to keep the real-time bar no less than 20 mpg until I reach the desired speed (usually it takes a "20" to accellerate and keep up with traffic). If I'm by myself, sometimes I can get up to speed holding at 40. Under most conditions, I try to get up to the desired speed in short order (i.e. the pulse in a pulse-and-glide) without being overly-aggressive.

At speed, I dial-in the gas petal to hold speed. This is what I've observed:

20-30 miles per hour is actually more difficult to cruise at. It takes 40-60 on the real time display to maintain speed on flat, level ground.

30-40 I can hold speed on the 80 MPG mark.

40-50 I can hold between 80 and 100.

50-60 I can hold closer to 60.

60+ is more difficult - takes 40-60 to hold.

Now that I've laid all that out, I cruise most efficiently between 35 and 55 miles per hour. Does that get at what you were looking for?

*** Retired after 65,000 outstanding miles ***