Hoping that everyone remembers the old adage, "there are no stupid questions"....

What are the real differences between Greenland and and Aleut paddles (the typical or 'standard' models of each as they are generally compared. I know that in the end there exists examples but no definitive example of each).
I know the Aleut paddles have ridges on the back side (the side that's fore relative to our kayaks as we use 'em)
Does this mean Aleut paddles are generally considered to be stiffer than Greenland?

Are Aleut paddles longer/shorter, blades wider/narrower, loom cross-section contribute significantly to how they work?
Is the way they are used significantly different?

I'm curious because I'm still chasing that pair of 'ten knot' baidarkas that Captain Cook observed. I've got two pieces of redwood glued up waiting for more than a year to be turned into something.
My Greenland is busted in the middle; which I'll probably just fix. Maybe the blank could become an Aleut paddle. But I'd like to accomplish something more than just matching a style.

Thanks
Will