I agree with David on this.
That said, some folks with balanced and aligned chains did still experienced skipping, wrapping, or both. I implemented a simple and cheap chain wrapping solution early and never had to think about it again (of course, I also never experienced either problem, but it is hard to say whether that is because I took the time to balance the sled and get the ring height correct or if the chain wrapping solution took care of it.) So YMMV and you may wish to implement something along with getting your chain angles correct.
Please note that the chain should be parallel with the sprocket on both the sled side and the slack side for best operation.