It may even be that you don't need a channel or cut-out, and that if your sitbones are supported, your "parts" will be lifted off the saddle. That's the principle behind Knott's cut-out test.
Not only is the Butterfly overly padded for me, all Terry saddles are too wedge (pear) shaped for me. What happens with me, apparently with a minority of people on a saddle too wedge-shaped, is that the pedaling motion forces me forward along the transition area until my parts are sitting on the nose. So no matter how wide the rear of the saddle or how generous the cut-out, if it's too wedge-shaped, my sitbones won't be on it, and my soft tissues will get ground to hamburger meat.
Besides the return policies Muirenn mentioned, Wallingford Bikes offers a 6-month trial on Brooks saddles (you might be surprised), and you could google Selle Italia for a local shop who has one of their test kits. Last I looked, not all SI saddles were included in their test kit (they have a very extensive line), but if there's one of their saddles that's the right shape and size for you, that could be a way to test it also.
Last edited by OakLeaf; 11-27-2012 at 11:21 AM.
Reason: wrote between when I meant behind. good grief
Speed comes from what you put behind you. - Judi Ketteler