You only put one shim under each side, which one depends entirely what angle you want to run. The wing would then sit on top, then on would go your washers, all held in place by the pins. If its still loose, I can only imagine the holes in the wing are to big? I can honestly say it's not a problem I've had so I'm a bit confused. As Carl has said, post a picture and we can have a look for you.
