Here’s the stiffener blank with the wing rib form block. I decided to try the method outlined in the BearTracks newsletter to form the bend with heat from a torch.
To establish the correct bend you screw the stiffener to the wing rib form. Here the stiffener is captured under a large washer screwed to the form. I left the washer just loose enough to let the stiffener expand as it heated up. I drilled a hole in the fore end of the stiffener to attach it to the form.
You can see that it has quite a ways to bend to mimic the airfoil shape.