The Gingery Book is a very good guide with lots of good info. By Gingery type I am pointing out the 3 part design of the main body which allows for easy (and safer) access to the crucible. Most other aspects are different, the size, lift mechanism, mobile base, preheat rack etc. are all my creation. But if you follow the info in Gingery's book you should be able to build a furnace that serves your needs.

Carlos