Now that is brilliant and likely never would have occured to me.
One thing I have discovered about enhancing the clouds. After completing the conversion and bringing them out as best I can in OnOne software, back in LR I applied a mask to the sky and used the clarity slider to bring out yet more detail/contrast. Worked good.
Oh clearly I've now begun a one way journey down the monochrome path. It will definately become a larger part of my bag of tricks. If for no other reason than to try and capture the feeling of the miserable weather we can get on the sound in summer. After all, when it's happening the world looks B/W in person