As Piker20 stated the force of the current even with your heavy tips will tend to straighten the fly out during the swing. However in my experience with fishing the Skeena the nature of the river bottom should be considered. I have found using a heavily weighted fly and a fast sinking tip on this river is a recipe for lots of lost flies. You might consider a very fast sinking tip, a non weighted fly on a 3 - 5 ft. leader this will allow the fly to swim close to the bottom and not continually getting hung up on the boulders. I have found as the fly completes its swing and drops down in slower flows a heavily weighted fly will snag, this is the area when most takes occur. If you feel the fly is not getting deep enough try a longer T14 or T17 tip, the unweighted fly will of course follow the leader down but will tend to ride above the boulders.