The skin shader seems to be a really good choice for this as it comes closest to the Arnold standard shader. Multiple spec channels and direct control of color lengths.
edd: did a quick test. Some things still have to be adjusted. However, it's much simpler than layering either inside the channels or using the layer shader, + the three scattering options are pretty good to define the low and high-frequency noises. It's easier to change the look, from icy or powdery to wet while maintaining details that might change too drastically with only one scatter channel.