A good question that I can't quickly answer.
The now closed Spokane Art School used to have classes. I know some of the High School jewelry classes cover it and I think one of Pete Jagoda's classes at SFCC includes lost wax casting.
Metalman (Kurt Madison ) may have some suggestions next time he logs in.
The Spokane Jeweler's Guild meets next week at Rings & Things. I'll ask the members where you can take a class.
In the mean time, this article gives a good understanding of the whole lost was casting process at a commercial casting shop. Larger casters use vacuum assisted and more automated equipment than the bent arm centrifugal system shown but the process is basically the same.
http://www.silverenchantments.com/lost-wax-casting-process.html