Well I sure don't know much about knifres but I can offer some advice on knives.
The 2 is a thick beast. Near indestructible but the thickness hinders it's performance in a lot of general cutting tasks. If you want a blade to serve as a true "survival knife" that you don't have to worry about breaking should you get into a bad situation and have to abuse your knife then that's the one to get.
As part of a system the 16 is probably the most handy. Light and nimble it's great for the typical stuff you would use a knife for while the machetes, axes, and other choppers handle the rough stuff. Still very tough if you need to beat on it.
The 10 is great to grab and head off for a few hours if you don't want to bring a bunch of gear. Thin and light enough to preform well but strong and large enough to get you through if something goes wrong.
The 7 isn't quite as handy but it's certainly capable of anything you might need to do, though possibly with a tiny bit more difficulty. Personally I don't find a lot of use for knives in the 7" range. 3-4" for EDC, 4-5.5" for outdoor utility mundane stuff, and 9+ for gathering wood or clearing a path and the other big jobs. I have a few 7" blades though and they are far from useless.
