I've checked out many Co-Pilot posts and videos. One question I still have is whether one of the side pockets (next to the water bottle compartment) could comfortably hold a big kids/small women's jacket that is light, but a bit thicker than nylon windbreaker shell type.
I want to use the bag mostly as a light brief/tote for day trips, going out, etc. (more than for "traveling"). I'd use the big compartment for books, papers, and maybe a netbook. That probably wouldn't leave much room for a jacket. I don't like stuffing compartments so tightly that it's a struggle to load things in and pull them out.
I'd probably only use one of the small side compartments for gadgets, small personal items, etc., leaving the other side compartment free for something else. So, I'd hope to fit my sweater/light jacket in there, but it seems like it'd make the zippers explode.