In your opinion, how much wiggle room does one have when painting aspect warriors, assuming that I want to create a more or less "correct" - perhaps a better word would be "fluffy - Eldar army?

Can I play around with the exact distributing or shades of the colors - dark angels green instead of black on dark reapers, for example - or add actual metallic silver to my shining spears, or add the colors and symbolism of my Craftworld to my aspect warriors' banners? Is this the sort of thing that one would see in the world of 40k, or would that choice take my army entirely outside the bounds of fluff?

Thanks in advance.