Originally Posted by
elcruxio
The cervelo seat science web page instructed that the saddle should be at least 2cm wider than the sitbone width. With that, I would say go with a 146mm
The form, shape, canal/no canal is up to you. try out different kinds
That's pretty good advice on that page. IT width plus 2cm. You can go wider as long as it doesn't chafe, but not narrower.
But that's only the starting point. Pelvic rotation and rider posture have a LOT to do with picking the shape and even the width of a saddle.
As far as Brooks saddles go (since it came up, and since I ride them too...)
Max sit bone widths to model are approx: 95mm for Swallow/Swift/Colt. 105 for B17N. 110-115 for Pro. 135 for B17. If that seems extreme, it's because you can only count the area BETWEEN the frame/cantle plate as "useable" saddle. So it's about sit-bones plus 4-5cm for a Brooks-type saddle, depending on frame size.