+another brooks lover here.

B.17 is hard to go wrong with, but if you spend most of your time upright you might benefit from the springs on a Flyer. Its essentially a B17 with springs, very stiff springs.

Don't be terribly concerned about fit. They mold to fit you over time, so it will ina few months time become your most comfortable saddle. I thought mine was nice the day I got it...9 months later Its broken in and more comfortable than I could have imagined possible. I had the chance to ride a properly cared for 30 year old Brooks Professional over the weekend...it was like sitting on a pile of charmin

Unless you have a really narrow butt you probably don't want the B17 narrow.