Hi,
The ideal moiture content, for any bow wood, is around 9%. Most kiln dried wood is around the 8 - 10% area, so you really don't have to do anything with it before you start, especially if you're making such a light weight bow. Hickory and oak are really poor with too much moisture. They take a great deal of set, and have poor cast, if they're too wet. If you've found a nice, straight piece of anything, make some sawdust!!