Split Lobe Separation Angles?

I rarely use rollers. I won't use a hydraulic roller without an arguement, but eventually the customer gets what they want.
That being said the money is better spent elsewhere if I don't need anything special to make the required power. It is a rare scenario that a shelf grind can't satisfy my power needs. But I know how to match components. It might be better for a novice to pick up a phone.