Personally, I'm inclined to go with the longest rod and line combo that fits where I'm fishing. My home river, the Methow, is pretty small and most of it could be covered with an 11' stick but I often find myself using 13' to 14' rods with mid-bellies as they give me a greater ability to steer my swing into the smaller buckets across the whole river. On the CW and Snake, skies the limit. Might use a 12'er, or even a single hander, for some of the small pockets along cut banks, but on most of the runs I seldom use anything shorter than 15' and prefer 16' to 17'. As far as summer and winter rods go, I almost always prefer longer rods in the winter when I more often use sink tips. I find the greater lifting ability of the longer rods to be a significant advantage here. Use skagit heads as seldom as possible and much prefer short bellies (e.g. SalarFinder45, Rage...with 15' tips), mid-bellies (WA55) or even long bellies (WA70) with tips in the winter. I've seen enough winter steelhead caught on size 14 Prince nymphs, and caught enough of them with my summer style flies, that I am quite certain that a 4", lead eyed Intruder is not required...or actually might be a disadvantage. Hence, no need for the huge freight moving capacity of a skagit. If I can't readily use singles and snakes, without rolling the tip to the surface first, I'm not very happy; hence the long rods and relatively longer lines. Fishing needs to be fun and not just a utilitarian exercise.
For my next Deschutes trip the central rod in my arsenal will be a 16' 6/7wt prototype with a WA70 6/7. Even the little 5 pounder's will bend that thing in half and I'll be able to steer my bug into and around all the boulders and slots! But in the interest of full disclosure I'm almost exclusively fishing interior Columbia Basin tribs and summer run fish, not winter run fish on the OP. Now, in the interest of even fuller disclosure, I have been advocating for, and I believe B&W is pretty close to having, a 12' 6wt Powerlite. That stick, and the 12'6" that the OP recently acquired, will be tons of fun on rivers like the Methow, GR, Deschutes, and all sorts of places in southern Oregon and northern California. But when it's all said and done the 13' 6/7 Powerlite is the one rod that is ALWAYS in the truck when there is even the most remote chance of a steelhead being in the vicinity. My .02
I see you're a shvingger too!
Bruce and Walker North America - Pro Staff