tbyrd,

Try a less cambered wing, even a symmetric airfoil, as opposed to a flat bottom. Not only is your thickness increasing toward the tip, your camber is as well. To control tipstall, use a little less taper.

Really, there is no difference, in terms of simplicity, between using different airfoils at the root and tip and using washout. Since you seem to value simplicity, a constant airfoil with less taper sounds like your kind of solution ( mine too ).

banktoturn