something bout 1 1/4 at mid limb ,, tapering at the tips,, either bend handle or narrow deep handle with fades ,, what ever you like,,, just take your time,, there are alot of great designs,, I prefer simple,, this would be osage,,, little wider on a white wood,,, the main thing on a stave is to keep the taper even,, even when it roller coasters a bit you have to follow that,,,
you cant just make the belly flat,, you will have weak and strong spots that ruin your tiller,,,and break the bow,,