Someone recently showed a quick painting technique for Iyanden, I haven't the wherewithall to search right now but I will edit it for the link.
EDIT: http://www.thedarkcity.net/t7073-iyanden-stuff?highlight=iyanden
Essentially it was washing a white undercoated guardian with yellow a couple of times before highlighting.
I thought it was great so I put my washes to the test and thought people might like to see the results, Only four at the moment but will add more as I acquire more.
Anyway here's a group shot:
This one is drakenhoff night shade on the left and carrebourg crimson on the right:
This one is cassandora yellow on the right and biel-tan green on the left:
They were all washed twice.
Personally I think the drakenhoff night shade is fantastic and will be using that for craftworld/corsair allies.
Hope this is useful anyway.