should work well with that clay...as long as you mean smooth out as in refine the surface (some people hear "smooth out" and think it is going to get rid of bumps and deep tool marks on a rough sculpture and its not the case)
as for the monster makers stuff, its kind of a mix between oil based clay and wax, and the wax doesn't want to smooth out with most chemicals (heat is the best way with that stuff)
in general i'd sugguest Chavant NSP medium hardness clay.(or hard if you are sculpting something with hard edges and fine detail like a helmet or something)....its the best all around clay i've used.