Best I can remember from my highschool geometry class, it also depends on how the ratio is measured, the rocker ratio is going to give you the most lift multiplication when the center of the roller tip to the center of the rocker pivot line is exactly perpendicular to the valve center line, this generally happens between 1/2 and 2/3rds lift depending on what tran of thought is followed in setting up the geometry. If you measure ratio only at max lift you will need a rocker that gives you more actual ratio at mid lifts. PR length and valve angle as well as some other stuff can all throw a wrench in the calculations.