Written by Kris Lapoint around 1997:
Where you place the wing on the fin makes a big difference–no, make that a huge difference. Even on the same ski, you may position it differently than another skier would place it. It takes plenty of trial and error to find the optimum location, but it’s worth the effort. Here are some general guidelines for adjusting your wing position:
Moving the west wing toward the rear (putting the trailing edge of the wing about 0.5 in. From the rear of the fin blade) pushes the ski out in front of you in the turn and makes the ski finish the arc more quickly. This is especially good if your ski tends to finish behind you at the end of the turn.
Moving the wing forward, to about middle of the fin blade makes the ski stay in the turn longer and helps keep it underneath you while finishing the turn.
Moving the wing up the blade, toward the bottom of the ski, lets the ski roll up on edge easier in the pre-turn and may slow the ski slightly more than a lower placement.
Lowering the wing placement provides more stability. The ski feels more locked in and is also harder to roll up on edge during the pre-turn.
Wing angle is a totally separate issue. If you are using a wing, it has got to have some downward angle. The minimum is about 5 degrees and the maximum about 124 degrees. Common knowledge says the more angle, the better the ski slows down and the more drag the ski encounters while traveling across wakes. I don’t disagree with this, but wing angle plays another important role–it also affects how the ski turns. More wing angle promotes rounded constant-radius turns, while less angle yields a turn that’s slower to start with but very hard to finish. Most skiers like the characteristics of more angle on their off-side turns, and less angle on their on-side turns.
Like a lot of things, with fine tuning your ski you must find the best compromise. Spend a lot of time trying new locations and angles you think might not work. You may be surprised how much difference it will make.