For canoe tripping, I'd go with a two- or three-person tent. If weight is not an issue, you might as well camp in style. But for those attracted by the thread's title, here are my two cents for solo shelter when weight is a factor.
Years ago, including when I was working on the ADK 46, I used an 8x10 tarp in the manner DSettahr recommends. It works wonderfully well, and indeed will keep you dry in the heaviest of downpours. When hiking, it can be easily and compactly lashed to the side of your pack. I would bring a lightweight nylon rope, use
in situ twigs as stakes, and my emergency safety blanket as a ground cloth if the ground was wet.
Now however, largely because I got a pro-deal, I use the one-person
Big Agnes Seedhouse SL. With a packed weight of 2.5 lbs, the weight penalty is minimal. My one complaint is that, because the vestibule does not have hoop to help cover it, water usually gets into the tent if the vestibule door is open during rain. This is not a big deal if you're only opening the vestibule when you enter and exit the tent and, doing so relatively quickly, but it does mean that you can't have the vestibule open to cook in or for extra air/view when you're tent-bound by inclement weather. Solo tents, by nature, tend not to be palatial, however, I have never felt cramped in the Seedhouse SL.