That'd be a biomechanical study I'd be interested in. Effect of weight, optimal stride length, impact of skin track angle...I've tried informally but it's pretty hard to be rigorous with so many variables. I've done plenty in Oz on 108mm wide skis. If you could have only one ski for BC, I'd probably go somewhere around 105-108 width. It's definitely more to get from edge to edge, but something like the ZG105/108, Wayback 106, Corvus Freebird have plenty of edge grip for the steep and firm. And in anything soft or loose, they are that bit more stable than thinner skis.