Touring - Brooks rails question.

I find the rails on my brooks saddle bend in at the front too near the centre of the saddle. This means I can;t get the saddle as far back as I'd like it (I suspect my geometry is a bit odd - long arms, probably. It;s maybe only half an inch, but frustrating. I find myself riding up on the rivets too often. Other saddles I have are fine, and can be set back further. I know I could by a stem that sets the seat back further, but I tend to swap my Brooks around my various bikes, and the problem persists on all of them.
Anyone had the same problem, and, more to the point, anyone been able to bend the rails to allow for a bit more movement? I imagine that short of taking off the leather and hammering the rails, they aren't going to budge.
Anyone know if there's a variant with a straighter rail?

I really think your best option is a seatpost with more setback and hopefully all the seat tubes will accept the same diameter seat post so you can switch it out.

Yes, I suspect you're right. Only trouble is, certaily three of my bikes have differing seat tube diameters. Idid have a tube with a shim affair, but it was pretty hopeless - I could clamp it at the top, but the bottom moved about latterally.

if a centimeter (1/2") is really all you need: http://www.rivbike.com/products/list/saddles_and_seat_posts#product=11-070 might be the go for you

I've had the same problem with my B17, the rails are shorter than newer saddles. These saddles
were designed when all bikes had slack seat tube angles of around 72 degrees or less.
On newer bikes often the seat tube angle is 73 or 73.5 which make the desired setback hard
to achieve with the short brooks rails.

A seat post with additional setback of 1-2 cm fixes the problem, maybe more for long femurs.