Very nice looking bow!
Personally speaking, I'd say the brace shape is telling you quite a lot about some potential improvements to the tiller - top limb is bending too much just past the handle and very stiff at the tip, and the bottom limb is stiffer than the top throughout. You do want the bottom limb stiffer in general, but I think here it could do with bending more overall.
While it's not yet a hinge, that top limb spot just past the handle will almost definitely become a hinge as it's shot in. The rest of the limb is doing very little work, so removing wood from the tips down will help a lot, but of course the bottom limb will need to be weakened a fair bit to come into tiller.
Your other option might be to heat-treat that weak spot to stiffen it up, and then simply shave some wood from the upper limb tip, and the whole bottom limb to bring it round more. You'll keep the weight up, that way.
