A jumbo flyer would have been a big help here!
After starting, I decided that I didn't like the thunderbird design included with my pattern, and made up my own personalised charts featuring H P Lovecraft's Cthulhu. A face for the back, and a side-view of the seated stone idol for the fronts and sleeves.
I've been having an amazing conversation with a HSN reader from British Columbia. I've learned that it's fine to personalise these garments, but that the Cowichan people have registered the name for this style of knitwear. So as with Champagne or (close to my heart) Melton Mowbray pork pies, a Cowichan sweater is one that's made by the Cowichan families. So it's impossible for me to make a Cowichan sweater, but I'm told that it's fine to describe it as 'Cowichan-style' which I will certainly do from now on.
I've also learned that the traditional jumpers are made in one piece, not seamed as mine is here. There's a trade-off here. Knitting back and forth gave me the opportunity to use intarsia, so as to not carry the black across large sections of white. However, I'm also told that the traditional way is to weave every other stitch - which makes a very thick and robust fabric. That also means that every stitch is a knit stitch with the obvious advantages there.
I said in the title that it's (almost) finished. I've not sewn in the zip or woven in all the ends. This is because I think I'm going to wear it through January and February at home (it is incredibly warm) and then pull it out in order to knit another with the same yarn.