Your right about the needed shear webbing, I installed it on the front spar on both sides, front and rear. I might have added it to the rear spar too but dont recall at the moment. Your plane pulling to the left at touchdown could be caused by not having any right thrust and trimming for that will always pull to the left when the throttle is pulled back like at touchdown. The wing is really a simple build and easy to keep straight because of the flat bottom airfoil, dont be afraid to build it yourself, just make sure your build board is flat. I would love to help but Im in the Seattle area plum across the states from you. If you have any questions about the build I would be more than happy to help. It also might help your problem to put in a little washout on your wing tips with a heat gun or iron, just twist the wing a little then iron out the wrinkles. Make sure you get it equal on both wings. Twist towards the ground to lessen the angle of attack so that the root of the wing stalls before the tips. Hope that helps. JIM