The good thing is that there will be a lot of overlap between the knowledge required between the two, so that hopefully we can get a really good set of mats at the end.
Actually the main conceptual difference between paco's work and Lord Crc's work is that pacoés is a full simulation of the layers while Lord Crc's is a physically plausible reasonable approximation of the behaviour. The latter is indeed much faster, and can be extended to add diffuse coating, specular coating, ...
I've just pushed a few tweaks to both the glossy coating and the layered material. I've done some tests with glossy coating, but not much with layered material, so please report any issue you might find.