I’ve had a Brooks B68 for a few years now. It’s 205 mm wide; I have a fairly upright riding position; my back is about 25 degrees off the vertical.
Before choosing it I read the advice on the web which in general advocated measuring the distance between the seat bones then buying the narrowest saddle that ensured both seat bones were supported. If I’d followed that advice, I’d probably have bought a standard B17 – the best selling Brooks saddle.
My experience with other saddles had made me appreciate the buttock support of a wider saddle, so I chose a B68 and haven’t regretted it. Yet it seems I’m in a minority. Others in the group I ride with (we're fairly leisurely) have B17s. The B68 has been discontinued.
What have I missed by not choosing a B17? I’ve laced the nose of my B68 tightly, so I doubt that the saddle nose is significantly wider, if at all.