I would serious look into Polytech as they manufacture superior resin and for the same price as a Micromark or Alumibites kit, you get twice the amount of product and far better quality. Talk to a rep, tell him what you want to do and he will tell you what you need. These "kits" are a rip and bad quality, i learned the hard way.
More specifically, Polytech 1512 resin and Silicone Inc. P90 Mold compound is a winning combination used by the best resin casters in the states.