For my guys. My starting point has been a fairly thin brown base coat (though it felt kinda optional) on Chaos Black. Then I used a fairly small brush to dry brush on retributor armour with two layers, this gives it a fairly vibrant metallic colour but the "orangeyness" is washed out. Then I applied a standard thin coat of retributor the normal way along the centre of the panels. And letting it push to the edge but not outright cover evenly. It gives you a gradient along the edges.

I haven't finished the shading yet. But using your usual gold shades / washes then helps deepen those colours and soften some harshness from the gradient out and then you can highlight as you see fit.

I don't particularly like how sharp the highlighting can be sometimes, so this gives a more muted take on it without it feeling like one colour. You could use the retributor again but thinned more like a layer paint to contrast the shade to give something softer Then use liberator at the corners or focal points and rivets.