For what it's worth, and I can't speak for any of the glenl plans, but I grew up with a few pirogues, and have been canoeing quite a few times as well, and I can say that all canoes I have been in were much more stable than the pirogues I have been in.
They have much more freeboard (is it called that in a canoe) and I think I read and saw a great diagram in "Boat Building with Plywood" illustrating that a round bilge makes the boat less prone to tipping due to the bouyancy created....I give up trying to explain..
Check out the attached links I found interesting when I googled "buoyancy of round bottom canoe"
http://www.oldtowncanoe.com/canoes/anat ... ction.html - I Think glenl's canoes are shallow arch bottom, not full round bottom, so this is probably what you ware looking for.
http://www.voyageurcanoe.com/stability.html