I've been experimenting with Fresnel reflections on skin in PP12, or at least I've been trying to, but most of the time has actually been spent just trying to get rid of these artifacts I keep getting.  The skin rendered perfectly fine until I added the Reflect and Fresnel_Blend nodes to my shader, and while the Minimum Shading Rate seems to be the primary culprit, cranking it up to even 2.7 (worse than the default "Draft" setting) doesn't eliminate them completely.  I would greatly appreciate any advice you might have on how to fix this without sacrificing significant quality/detail in rendering.  Any ideas?  My Shadow Min Bias is 0.0169 (feet), and I tried raising it dramatically to 0.069 with no visible effect.  Raising ray bounces doesn't seemt to help much either.

Thanks in advance!