[tongzilla]

The Dual Hinge arrangement is not necessary to reproduce 10-10-C (Angled Hinging). That's because the Hinge Pin is positioned vertical to the Inclined Plane, thereby controlling both the Clubface (and its 'simultaneous Close and Layback' motion) and the On Plane Clubshaft.

In reality, the Angled Hinge Pin may not be exactly perpendicular to the Inclined Plane used (but still perpendicular to an Inclined Plane), thereby necessitating the use of a second hinge to control the Clubshaft.