Nice job.

Boughs aren't bad if you're cutting new ones which are thin and laying them down. Judging by your description they might have been a tad big. Putting a sleeping mat, even a thin one, on top helps a ton.

Also important to remember as long as you aren't wet, snow is a nice insulator underneath you, so a sleeping mat or two right on snow works too.

As some have mentioned, you're not gonna "canoe" in the winter, but realisticly what you're sleeping in is more or less like sleeping in a "snow trench" which you can then cover with sticks and a tarp with snow on top for the same effect.

I've used such shelters - and they are actually warmer than a tent. My only issue with them is dampness, not necessarily once they are up, but the exertion and snow digging required to make them in subzero weather. To do them I really need to have a full-on waterproof set of clothing with me, and ensure I don't oversweat while building it. Not to mention a lot of the places where I am (outside of the mountains) just don't get good snow for this type of thing in the winter.