I originally posted 65 % load or less seemed to be the requirement to get into lean burn. I now find up to 69% seems to work.
HOWEVER, in the range you're trying to hit - in the 60's percent - the numbers are usually very sensitive to pedal movement. So I just try to get it somewhere below 70. I'll adjust my foot, and the gauge might show 60-x or 50-x. Then as soon as lean burn kicks in, I give it more gas to take better advantage of the opportunity. If you're gonna turn that engine, you better be running some fuel through it and getting it to do some work for you!
Upper limit seems to be 91 or 92 percent load. But in practical terms, ESPECIALLY if the car is losing speed, I'll limit it to 88-89. Because if rpms are dropping, the same pedal position will give a higher load percent, after the rpms drop some.
Coast long and prosper.
We've learned that diet has a closer relationship to cancer than we ever thought. Please see this Wikipedia article on The China Study
Driving '96 Accord DX. Planning on an Elio enclosed three-wheeler, due out 3rd-4th quarter 2015.