in another life i was a fighter pilot and engineer, so lots of time studing aerodynamics and practiciing it.....so the viscosity theory is correct in my view. but on the wing it is not quite that straigtforward:  when you add lift you also add drag on any air foil and since water is many times more viscous than air, a small adjustment is mulitplied. a fin wing is similar to the elevator on an airplane and it intuitively adds downward "lift" to the tail of the ski, raising the nose, which is opposite to what the ski industry says. actually with a small amount of wing angle it does bring the tail of the ski down, and raise the nose of the ski, until you add more wing angle and then the drag of the wing overcomes the lift of the wing and it creates the opposite affect. i dont know where that wing angle may be and it likely changes from ski to ski or when the water temp changes, but for discussion sake, if the wing angle starts to be positive, or hold the tail down at say 5 deg it may actually lift the nose of the ski at that shallow setting, but........when we increase it say an arbritary 10 deg , drag is likely more than the lift it provides and the wing  will "put more tip" or ski in the water because of the torque affect. the distance from the center of drag of the wing to the center of lift of the ski, (maybe about 2 inches times the amount of drag force) less the wing lift will be the net force on the ski  .......so as we discussed, somewhere between 5 deg and 10 deg the opposite affect occurs from a wing because the net forces of lift and drag changes, thus the confusion in the ski industry and what people feel, not knowing the different affects a wing can have on a ski....also the size of the wing can obviously change the whole equation, as in the difference of a mini wing, or one of the big ones that is used on Goode skis, as well as, the amount of drag just the mounting hardware provides. ski speed will also change this drag/lift relationship, as the Reynolds numbers will change quite a bit from 32 mph to 36 mph. You could actually have a wing at the same angle lifting the nose of the ski at 32 and lowering it at 36 if the angle was just at the "breaking point" Bottom line: I think in most cases 4 to 5 deg of wing actually raises the tip of the ski, and 7 and greater lowers the tip of the ski affectively adding "tip". sorry to ramble, but hope it makes sense.