Well, with the cambered airfoil at the tip, your adding an effective angle of attack (due to the camber) to an effective angle of attack (due to the location at the tip).

Basically, your adding wash-in... which will make the wing more prone to tip stalls. The thickness helps, but is definitely negated by the other factors I mentioned.

Personally, I would go the other way around and use a cambered section at the root and a symmetrical section at the tip. In this way, you can lower your wing incidence at the root and have an "airfoiled" wash-out (that is, non-geometric).