Consider that the length and wt of the rod you use may depend more on the line, sink tip, and size of fly you will be swinging rather than the size of the fish hooked. Very few fish on the Skeena (or any other river) can over power a 6/7 wt spey. But 5 or 6 hours casting 16 ft of t-14 and a brightly colored canary size fly on a 12' 6" 7wt will be much more challenging than rolling the same heavy stuff with a 14' 8wt. Talk to your guide, he will be best qualified to help you with rod selection.