I've been measured using both the Bontrager and Specialized measuring tools, and on both I have measured out in the "medium" category - 143mm for Specialized saddles and 150 for Bontrager's WSD saddles.
I am considering the Brooks B17N (152mm), because I fear that the standard B17 (170mm) will be too wide and cause chaffing. Does this sound like a reasonable assumption?
No, it sounds like a B17N would be way too narrow for your sitbones. Try a B17 first, or even B68. I concur with Mimi in avoiding the "S" models. I didn't like the B17S much for various reasons. I've ridden both B17 and B68 and they are both great. B68 is for the widest sitbone span (me). B17 is for average width bones.

Then there is the Selle An-Atomica...which after reading over their website, really intrigues me. But again, I fear the width of the Titanico (165mm) would be too wide for me. I'm not sure if they are producing their medium-width Robusto saddle...does anyone here know? It is not offered on their website...looks like they are only offering the Titanico.
You might not want to order a Selle An-Atomica right at this point in time. Sadly, the designer/owner Tom Milton died recently during a double century ride, and it looks like customer service is not functioning much at the moment. they might need to settle the estate before others can continue making/selling the saddles:
http://audaxvermont.blogspot.com/201...-lives-on.html
Note the comment section.


Can anyone give me some insight on either of these leather saddles? I don't want to make another buying mistake.
Did.