Yeah, split it now. It will season just as natural as all get-out in stave form.
At least if you split it now you can control WHERE it splits. If you leave that tree "in the round" so to speak, every single check...and it will check....will be right down the middle of every piece you wanted to take a bow from.
Good luck with this log, sounds like there is some good bow-working material for you for some time to come!