Thanks for your help, guys- I've put about 350 miles on it now. I have found that tilting the nose to level/a hair below level helps, as does keeping the tension pretty tight. I also took a nail file to the sharp top edges of the cutout, which alleviated any issues that I had as long as the tension is good.

I have been tightening it during every ride, so I'm getting near the end of the tension screw now. I emailed Tom at Selle An-Atomica to ask if maybe I should exchange it for the ED model (less flexible). I'm hoping he works with me on this, because it's awesome when the tension is up, but as soon as it sags, I get chafed by the cutout edges (actually starting to get another cyst down there from it ).

Even with the cutout problems, it has definately been the most comfortable thing I've ever put my butt on. I get some ribbing from my teammates about how large and weird it looks, but I've found that all I have to do is invite them to sit on it once and they are amazed at the butt-hammock effect it has.