I would not choose a B17N for upright riding. It's narrower than the Pro and is like sitting on the narrow side of a 2X4. My favorites are the B17 and the Flyer. I also like my B67 and my wife's B18.
You can find good advice at wallbike.com. It's a good place to buy a Brooks because you have 6 months to return it if it doesn't suit you.
I disagree with the post above. The springs are stiff and only come into play on sharp bumps.