I don't have the huge snow amounts as the "white north", however we do have multiple sleet and ice storms, not to mention the numerous dust storms (we have a higher average wind speed than Chicago does). And we are called the "high plains". lol It's flat but we're also at about 3,000 feet above sea level. And mine usually goes to the Colorado/NM mountains several times per year.
That being said #16 will easily last between the last fall detail and the first spring detail for me. I haven't tried the Collonite myself, so no personal experience. But Nattys, #26, and the like don't come close in durability during the winters here.
Just be sure you're comparing apples to apples. I have a wax for my best look (natty's) and wax for my best durability (#16).
Subject always seems to get a little touchy for some reason.