The important factors are how much you ride, and your posture when riding. I don't think "sit bone width" matters very much.
I normally ride a hard leather saddle, and a pretty narrow one. But every work day I ride a couple miles on the padded vinyl saddle of a CitiBike (a saddle I would never, ever, put on one of my bikes), and I have no problem with it at all. For a fifty mile ride, I don't think I'd be able to tolerate it, but for one mile at a time, it's fine.
The saddles on Citi Bikes are horrible for me. I manage to tolerate them by sitting abnormally far back. On the Shimano-equipped model, I raise the seat a bit higher than normal, and on the SA-equipped model, I set it a little lower than normal, as the saddles are slightly different.
There doesn't seem to be much science to finding the right saddle for any given butt. The curves and forces on those intimate places are probably not very well studied, and maybe it's because people don't enjoy being measured and prodded there.
Wow, I don't think I ever used the words "any given butt" before in my life.