Since this thread has now wandered away a bit, let me put in a quick word for the B73, which is known as the Brooks that is most comfortable out of the box. it has twin rails and three helical springs, one at each corner, and I love mine. It does well with big bumps but I ride on 60mm Big Apples with minimum pressure, so it needs to be a pretty big pothole before I pay any attention; i don't have to post often. On other bikes with high pressure tyres saddle was a boon but it let through road chatter, as said earlier in the thread, but not as much as expensive gel saddles from Selle Italia and Terry. Extremely comfortable from out of the box; I soaked the leather in neatsfoot oil for 20m, not long enough to sink in, just enough to apply a good coating to both sides, and twice a year put on a very thin layer of Brooks Proofide on only the top side.
One downside. The nosebolt is a split design, one bolt from the top, one from the bottom, inside the helical spring. Both are old British spec bolts, and if they come loose the nuts inside the spring are hell to reach and tighten because you can't get even a cone spanner in there. I finally solved the problem by holding the nut with a ground-down Bentley brake spanner (that's at least fifty quid down the drain already...) and twisting the spring. It's a kludge and, as such, unsatisfactory, but the best I can do.
Also good thick leather. In a major incident with a broken road a few years ago, the saddle was scarred through the top layer on one side in an area about half an inch square. I simply rubbed the wound with a good spot of Proofide on the Brooks cloth, let it sit 24 hours, and polished it off, and now it looks like a feature on an adventure bicyclist's saddle, not obvious or jarring at all. That's quality leather.