DC, 4" Same width as the handle.
Stick Bender, you're right, there are unknowns and I'm making a few assumptions. I'd love to have seen that bow unbraced before tillering, and unbraced again after 1000+ shots. I'd bet my best osage stave that if it took any set, the bottom limb took more set than the top. I'm just commenting on what appears to be going on in that one pic... assuming, odds are, it started straight unbraced, with the arrow nocked as is normally done.
Limbs can each 'bend smoothly' in their own right, but be FAR from balanced.