Thread hijack...
Does anyone know of a flat, non-cut-out, T-shaped saddle that isn't a Brooks? I'm having a similar problem, but my three attempts with leather saddles were not successful. They never got comfortable and the last time I got numb everywhere that the saddle contacted and stayed that way for two weeks afterwards.
My all time favorite saddle was a Vetta Triathlon ca. 1990 or thereabouts. Flat, 155mm width at the back, not overly padded, but with a thin flexible shell. Naturally, they stopped making it shortly after and then got out of the saddle business altogether. I recently tried a Fizik Arione Donna because it looked a bit like the Vetta. It solved the pressure problem up front but chaffed terribly under the back of my leg, in the same place described by the O.P. of this thread.