Param B cannot be changed. It's a leftover from Cloud Layer V2. It might be removed, or I might map it to some other parameter in the future.
Param C is very difficult to describe, I'm afraid. I'm not sure what the ideal range of values is, but it does affect the appearance of the cloud and I feel that more tests need to be done to understand how it affects the results. So I'm exposing it in the GUI so we can experiment with it.
Matt