Kip...the Bark on Sycamore will pop off just like the Bark on Vine maple does as it is worked into a Bow...so my answer to you is split it...debark it...and seal it all up...I like working Sycamore and have made several working Bows from it with no problems so far....as for the Twist...once you split it...and debark it....and the Shellac is dry....clamp it to something to keep it from twisting up on you...if it is already twisted...steam it and clamp it down to pull it out while it is still wet...this isn't a large stave ...so it should not be too hard to pull the twist from it