When I got measured at the Specialized shop I was between a 130 and a 143 (I think I was 141)...first I tried the 130, but felt like half my butt was hanging over the sides. The 143 was much better.

I do tend to scoot up onto the nose of the saddle, I've noticed. I do that to avoid the chafing I get (on the inside of my crotch where my leg "ends") which happens if I sit too far back in the saddle. T-shaped saddles work better for me based on experience (as I've tried the Selle Italia Lady Gel Flow and other more pear-shaped saddles to no avail).

The Brooks B17 fits me well, too, but since I've only logged about 50 miles on it (it's on my grocery-getter bike), I don't want to "break it in" on a century, you know?