I don't have a lot of evidence to support my claim (like years of work, or 100s of examples). What I do have is one figure with a whole lot of attempts, all from a single sitting!
From the first figure above, dark to light silver was easy, especially on the chest with big defined volumes.
On the wing backs I tried doube or even triple blends, dark silver, ligt bronzento silver. Copper to silver, dark bronze to silver, etc.
The photos are a bit crap, but it was super easy compared to normal blending. The wet blending was also attempted, but it was actually harder, which is odd, but not totally unexpected, metallic paints are funny.
Cheers,
HMP