Luke, and Big-O
You can rough out some of the twist, but don't expect to rough it all out. Here is my advice (I love Black Locust and it's about all I work with) - let it dry whole for as long as you can stand to wait. At least a couple months. 3-6 would be best. This will help it to not twist and warp even more when split. Once you do split it, if there is some propeller to it, it ain't the end of the world. MOST of my bows have some twist. I'm working on an ugly little BL stave right now that is twisted real bad. But myself I just don't care as long as the tips line the string up with the handle. Good luck on it!
-CP