I've got a civilian and looks comically large when I put it on, but I'm relatively small. You're a good 10 inches taller than me too, so it won't be a problem for you. It's definitely bigger than my old Timbuk2, which bugged me for a few days, but now that I'm used to it I don't mind the extra bulk and it's awesome when I need to carry a lot of stuff.

Don't you have a ruler? Measure your current bag and compare that to the specs of the new ones...