Can large pieces of slipware be dried without a kiln? I have a clay (plasticine) positive of a human figure standing 5' tall


Next step is making a rubber mold for the lost wax process and a bronze positive
May I use the rubber mold for slip after the wax positive is made, plaster is to fragile and not at all charming
Is Raku the answer for drying, if I can make a slip positive 
Would someone discuss the basics here?  Any pointers are welcomed, if they reference the project!  
The actual mold has multiple pieces that will be joined to form a container into which the slip may be poured and later poured out when the piece reaches the desired thickness.
Suggestions on thickness and etc.
Ideas other than plaster or slip
Making a piece out of ceramics, you should use plaster for the mold as it draws out the moisture from the clay slip, and you will not  need to  wait a  long  time to get the thickness of your  clay.  If you use a rubber mold, the moisture has to leave the clay through the  air, which is very slow.
Raku is a way to fire the clay, so unless you want a hardened piece out of the clay, I would not fire it raku style or otherwise.
If you are wanting to make a bronze piece, why use the ceramic as part? You can make the finished piece in several parts of bronze or clay.  The pieces  can  be  combined  afterward; molded clay glued with slip, or welding or soldering the bronze.
Another way would be a breakable mold for the entire piece, where you break the complete work out of the mold in one piece.