I would emphasize the importance of radius rather than width in carving ability.
The Rossi Soul 7 is 106 underfoot with a 17m radius. The Blizard Cochise is 108 with a turn radius of 28.5.
The difference--the Soul 7 widest dimensions are much farther from the tip and the tail, creating a much shorter carving profile.
Stiffness and camber matter more than width as well.
If you want to know how a ski carves either demo (best) or read professional reviews (next best) or amateur reviews, or ask on a forum (worst, unless you want to hear all possible answers from "terrible carver" to "best carver I ever skied"--mostly from people who have only that ski and haven't skied anything else in the last ten years, or demoed it once in the wrong length with a bad tune. . Look at camber and sidecut profiles on the manufacturer's site and also look at construction--core material and presence or absence of metal, to get an idea of what the ski might be like. You can't tell if all you look at is width underfoot.