This tutorial for a dielectric material preset relies on the IOR to dial in the rest of the values for a physically correct dielectric material. This was created mainly as a shading tutorial using modo 501's schematic view, material nodes and channel modifier nodes.
Typically the user will still be able to input a specular amount even though its not a physical attribute of the material but rather a faking of light hotspots. Users can also easily follow the tutorial and disable the specular channel.
Here is the material preset for those that want to check it out