I tried Cx5 , that's an excellent wax.
It's rock hard and you can smooth it with sand paper and then zippo fluid ect..
But if you want to use it as a "clay-like" material, you have to be VERY fast before it cool down.
The fact is that very few wax can be sculpt by hand first and then finish it with wax pen and smoothing techniques.
I would say that's a great Castilene alternative (Cx5 will not burn like Castliene).
here is a 1/2 C.reeve head I made in Cx5