I am looking for input on which plywood sea kayak plans are for very stable designs good for touring. We are novice kayakers looking to build a design from plans for a week long trip on the west coast of Vancouver island.

Where on the west coast of Vancouver Island are you planning to go?

I've paddled a bit on the west coast as well as some other areas around Vancouver Island.

If you are novice paddlers, perhaps hooking up with a professional kayak touring company (some provide instruction combined with a tour) might be an option.

In general (in my opinion) when conditions get windy/rough, kayaks which feel 'very stable' for novice paddlers don't perform as well as boats that may feel a bit more lively in calm conditions. I had the same feeling you describe ( I was tense and tired after paddling in just about any boat) when I first started paddling but once I took some classes and developed a bit more skill, things got a lot better and the boats I liked were different.

The reason I emphasize stability is that I recently paddled a CLC 17LT in both flat water and up to 2-3 ft waves. The boat seems to be pretty unstable, especially in waves. CLC sells this boat as a stable boat great for touring, but for me, even a couple hours of constant tiny adjustments to maintain stability is tiring.

The Chesapeake 17 may perform better with a bit of a load in it- CLC describes the maximum 'payload' as 300 lbs.
I don't think many owners would describe the Chesapeake as a very unstable or lively/playful boat, but I may be wrong on that.

We would need good gear capacity and be able to accommodate paddlers 130-175 lbs.

Sometimes a 'big' touring boat with a lighter paddler can be a handful in wind/waves. Put some water bags or other ballast (sandbags or rocks!) in the boat next time you take it on a day paddle.

You've come to a good place (kayakforum.com) for suggestions. Another resource is http://www.westcoastpaddler.com/community/