If you have a choice between a cloud in which it's snowing, and a cloud at the same temperature in which it's yet not snowing, pick the one that's snowing! And while your airframe may be below zero, it may not be even in dry snow, and it unlikely to be below zero in snow that has already started to melt to make RASN.
Bookworm, in view of the fact that you won't know the temperature of a cloud until you're in it, how do you know which is the "best" cloud to fly in?
Before you answer the question, perhaps you would kindly outline your practical experience of winter operations and snow flying and what formal /paper qualifications you have to make such a statement?