Considering the cost of a double rifle, and considering the wet climatic conditions in coastal Alaska and BC - particularly if you choose to hunt and stalk in thick wet cover as opposed to sitting on a stand - I'd consider reconsidering.

By the way - you and your gear will probably be wet and cold during the entire adventure. I'm not trying to dissuade you in the least - just trying to pass along a realistic assessment of the conditions you are likely to encounter. In addition to the rain and snow, when the wind whips up, the air will be heavy with salt spray from the sea water - you can taste it, and see it on your clothing and equipment. My rifle was built for these conditions, at less than a tenth of the prices I've seen quoted for doubles.

However, if packing the double is intrinsic to the enjoyment of your hunt - bring a couple of cans of WD-40 and have at her.