I am not attacking Mr Toelle article, he has been the leader in French camo research. He has published many times his findings in RBG, Methuen, and FS595 for both metal and fabric parts, and, never with the caveat to add silver or gray to attain the desired color.
If Mr. Toelle article was to replicate the original colors by using the original proportions my question is do they translate to model scale? For me that was the problem with the silver at 42% of the mix for modeling purpose. I'm sure the colors can be found in tube form at any art supply store as you said, hell if I had the money to spend I'd mix them and use them as a reference for sure, but, are they available to the average modeler in standard model paint?