If you're getting a Serotta, you've probably got a pretty good LBS to deal with. I would start there.
You'll find your own perfect ride. My Serotta is very special to me, so fast & light. I wanted the saddle to be like that, too. Give me new technology, it's come a long, long ways.
Enjoy your new bike when it comes in. You picked a winner!
make sure your LBS has a saddle return policy. that's why we like wallbike!