Generally speaking, there is no point adding carbon to plywood to increase strength. Plywood is so much more flexible than carbon that the carbon ends up taking practically all the load. If there isn't enough carbon to take all this load it can break and leave you where you started.

Much better to use fibreglass, it has similar stiffness to plywood.

On a productive note, some uni fibreglass down the inboard gunwales from cb case to bridle (roughly) might not go astray.

The kite isn't necessarily the greatest load on the bows.