I came up in the days when sitbone widths were never discussed. I still don't know what mine is. Or any of my saddles. I am not at all sure that would be the governing issue the way I ride. (Basically old racer style, quite a lot of forward bend despite being 70 years old.) I use the entire saddle length and have ever since my first race or earlier; many years ago.

For me, it is the entire saddle shape that matters and the only way I know to find that is ride them. I find the details up front under my perineum is at least as important. Also, can I push back further for "on the tops" power climbing? Does the saddle tail turn up and impair my broken tailbone?

I love that there are bike shops that take returns on saddles ridden enough that you honestly know whether they work. Portland (OR) has a shop that takes this a step further. You buy a "library card" for $25. This allows you to take out any of their 2 dozen saddles and ride it for a week. Find one you like? Buy a new one and get your $25 back.