I would suggest scrolling down a smidgen to the point in the article where it says "colours for NMM".
Right, but that specific article's "Colors for NMM" section gives only gold, steel, and silver recipes.
Chrome, in painting, I find to be more a concept than specific colours. If you want a brown earth/blue sky chrome scheme I'd suggest painting as standard steel SE to get the correct impression of shadow and horizon, and then doing some very light glazing with blues and browns to give the impression of reflection. The second link I posted does show an example but IMO it's OTT and cartoony and would be better served by a very gentle tinting rather than overt painting with block colour.
Look at the helmet as reference, it comes out best in pictures compared to the body. Also keep in mind that this was my first time having a serious attempt with this technique and, as with you, intuition as to where to place certain levels of highlight could do with work.
The bottom picture pretty much shows the helmet without specific light catching it away from my "imagine" light source. You can see in the upper two the way that the surface responds when the light is caught. Nothing especially long or complicated has been done to achieve this, the only thing I used which you might not have access to is my Vallejo metal medium, which is a lot like mithril silver but lighter, and I only used it for the extreme highlights.
I used standard metallic paints (boltgun metal, mithril silver and Vallejo metal medium) and when shadowing I simply mixed the boltgun metal in with progressive larger quantities of greys and, for deepest recesses, black. I only used flat paint with the metal for the lower, shadowed surfaces because I wanted the upper surfaces to really catch the light regardless. Use of the flat paint mixed into the metallic means that when the surface isn't directly catching the light pretty much all you see is standard shading, and (as the middle picture shows) when it is in the light you get a good amount of response to give the impression of metal.
More time can (and at some point will) be spent smoothing out the blending, and also tinting the shadows so that they reflect their immediate surroundings (skin tones and glow effects). I don't like the concept of blue/brown SE on stand alone models as I find it looks (as I mentioned) a little cartoony, a little showy and doesn't serve much purpose. A lot of effort for a negative result. Within a diorama it can be much more justified.Edit: High polish (chrome) reference pictures
. IMO there isn't that much colour that would translate into blue, considering a lot of the sky at any one time is largely white fluffy cloud. Also green is more predominant than brown by a long shot. When selecting tint colours for chrome you have to be mindful of the surroundings to convey that into the model, mainly why I only like it on dioramas.