I am getting the dreaded shimmy as well. In my build I opted to not add stiffeners to the main gear until I tested to see if I needed it. The shimmy isnt real bad with just the tap of a brake to turn slightly and it goes away. But I have noticed that on grass and unimproved strips its much worse. So, I'm going to add the stiffeners soon. I saw a guys plane once who added a shorter but similar stiffener to the back side of the nose gear leg and it seems to work so Im gonna try that too.
Mike