Those are already compatible, they just predated GW and aren't branded as such. Put 'em in the alpine position and go. Converting to the newer GW...

Anybody have a comparison between those and the OG Cochise?

What's the fit like (97mm last obviously doesn't cover everything, by a long shot)? I've never been able to find these to try on.

Nope. They're steel, but with much smaller teeth than the 18t (there's no 16t) as noted.

Yeah. It's sweet, having all the easily accessible storage on the shoulder straps is great and it carries very well for more moderate loads.