I,m just triying to answer AllenReads question. I think it's important to level my sight to my riser. He can do what ever he fells fit with the info!

AllenRead- If you want to set your level square with your bow, do it off the riser, not the string. The reason for this is that some bows' string is not parallel with the riser edge. Some one-cam bows have the top idler wheel centered in the limb forks, but the bottom cam has the string groove off to one side of the cam and the cable groove on the other.
Longer distances (as well as uphill and downhill shots) will require the leveling of the third axis to be consistent in bow position.

You can cant your bow all you want, as long as you do it the same way every time.

Thanks for the information!
Allen