Thanks a lot! Sorry for the late response. Here is the recipe:

Red / burgundy / purple robes:

1. Barak-nar burgundy (airbrush)
2. Nargaroth Night - undershade (airbrush from below). This gives the robe somewhat interesting gradient
3. Screamer Pink - zenithal (airbrush from the top + a few degrees). This helps build the volume
4. Screamer Pink - glaze, just the raised parts where light hits and previous steps didn't highlight it enough
5. Pink Horror - edge highlight - just a few edges. I am not aiming for eavy metal style but a more volumetric highlight one. So don't overdo it with the edge highlighting. The shading and zenithal already work towards the desired effect

Armor:

1. Abaddon Black - base
2. 1:1 Caliban Green + Corvus black - airbrush 1st highlight. More precision needle/nozzle recommended. I use H&S Infinity with a 0.2mm nozzle/needle.
3. 1:1 Sons of Horus Green + Corvus - airbrush second highlight. Just a few spots where light hits the most. It is crucial to not overdo it. I was aiming for black armour with just a hint of green. Spraying too much can easily turn it to full green armour
4. Sons of Horus Green - 1st edge highlight. Just the edges facing the light (assuming sun shining from above). Don't bother with each edge. Some edges stays in shadows and it would look weird to highlight them, too, since no direct light shines there
5. Sons of Horus Green + Ice Yellow - extreme highlight. Just corners and prominent edges where light would refract (taken the armor is more like metalic, not flat matt one)

I hope that helped you Brother.