I'm not sure if it' the material or how it's constructed or both, but it's impossible to make the tri-star really bulge. When I got it, just to see, I tried to cram as much in as I could. It seems to go inward, rather than outward, if that makes sense: if you pack a section too much, it takes away internal space from another area, not bulge outward. I don't know if that's true for the aeronaut or not. In a couple weeks, we're going to have all the bags together, so will see.
Just bought a med. cafe bag in black/steel for when I don't want to carry my heavy, big leather purse. Also picked up a few key straps, the wallet, and a couple organizer pouches.