In a normal custom glass I would use: Reflection Bias [0, 1] + 0.5 to power a regular fresnel output [math power(fresnel, result)], and let that drive mix shader of refraction and glossy. So basically I’m reshaping the normal fresnel output with a power function. Basic stuff, and doesn’t touch the extremes. And would probably work for a custom fresnel which accounts for a single roughness.
What would be the proper way to setup a custom glass where two different roughnesses are used (i.e. smooth reflections and rougher frosted looking refractions)? Should I use the custom fresnel governing refraction or the one governing reflections, or something completely different? Am I even attacking this correctly?