Questions about Canvas.SetMaterial, and IMaterialModifier

I have a bit of confusion about the functionality in UGUI with materials. It seems that Canvas.SetMaterial throws errors, and seems like perhaps it is erroneously exposed. I would usually use IMaterialModifier, but it looks like this is potentially getting deprecated (it isn't in newer versions of the docs). It is also possible to set this directly on the Graphic I believe. What is the best way to set materials on UGUI objects?