Bend test looks OK. Might as well give it a go.
Last chuck of hickory I had was 5 1/2" wide also and I sawed two staves out of it. But it didn't have any bark on it and things were much easier to judge. Got two staves 1 3/4" in width. But the back was kinda flat to start with. More crown means less width. So, if you want two staves, you're going to have to saw/kerf dead down the center. Here's how to find the center:
Removing that bark is probably going to test your patience with a draw knife but that's where you should start. Once the bark is removed, and if no defects to work around, then clean up the stave's sides to where you have at least 5/8" reveal on the side(s). This will help give you the exact center of the stave. Mark each end and straight edge. Once sawn/split, and allowing for a side reveal on the staves' other sides, will give you a good idea of their widths.