Allen key vs. flat wrench
Some of the more expensive Brooks saddles (e.g., Swift) use an allen key for tensioning the saddle. Most (B.17, Team Pro, etc.) use a flat wrench. The little chrome Brooks wrench, which is available at a variety of retailers and costs 5-10 dollars, definitely makes the job easier.
The advice above about not tightening the saddle is, IMHO, correct. I've tightened my B.17 just a bit (no more than a turn) but I found that lacing the sides was much more effective in preventing sag. The leather currently used by Brooks seems to be less "hard" (which makes for easier break-in) but it can also result in the sides flaring out when you put weight on the saddle. By contrast, I have an old B.17 from the 1970's that is still "hard" and keeps its shape perfectly, but is also very comfortable. I think Brooks should sell the B.17's with the sides laced (kind of like the new B.17N that you can buy laced for an upcharge from Wallingford). Hope this helps.
Dr. Bill (who did a 200K Brevet yesterday on his B.17 and whose bum feels OK this morning)