The Rough-Hewn Shore

[Dune]

Either would work, I'd say. I sometimes make the base color just W 0.2 and B 0.2 grey, so it's an even coverage.

[Tangled-Universe]

first design your displacements and only have a grey lambert shader as surface shader.

So you're only using the Lambert shader in this instance to check how your displacements are reflecting light, and then disabling it before a final render, thus enabling all other colours in surface shaders / power fractals / image maps to take effect. Or, are you using Lambert shaders for colouring throughout the scene instead of colouring with power fractals and image maps.

Yes correct, I only use a grey lambert to check the displacement and lighting. While doing this I disable the other non-displacing surface shaders to speed things up. Once it's dialed in I disable the lambert and re-enable all the other bells and whistles.
Obviously this only works conveniently if you organize your network somewhat and try to adhere as much as possible to the general modus operandi of displacing first and then texture so that the top of your graph is displacement and the bottom is texturing.
That makes for quick and easy toggling of nodes and is also the most fool-proof way of having everything work in a predictable and understandable way, without the need of being an absolutely god-like expert to find and exploit loopholes and exceptions to not having to follow the intented design and workflow of the software.
Feel free to shoot a message/tgd if you need any help...

[schmeerlap]

Thanks again Martin, Ulco. I received my new computer back from being repaired (power supply unit failed) and I've just re-rendered the Rough Hewn Shore scene with it. I did rein back on the Micropoly detail as you advised to 0.6, and upped the AA to 8, and the scene rendered in 1hr 13 min, as opposed to 3hr 15 min on my old machine.

[Dune]

It would be interesting to render some similar crops with different settings and see how much they differ in quality and speed. Might well be that detail 0.5 or even 0.4 and AA 6 only takes half an hour and doesn't overly hurt the eyes. At least low settings would be good for tests, until the whole setup is ready to make your move.

[schmeerlap]

Sounds good Ulco, but don't mention a low AA setting of 0.6 to Martin