I had the same problem. there are differnet size stacking lines you should have for different stack(6-8, 8-8, 8-10 etc etc) so make sure youv got the 8-8 length if you have got the right length then I found a good way to prevent wobbeling was to be more smooth on turning rather than doing sharp turns. And as said above the more wind the less wobbeling there tends to be.
Hope This helps:D