On further consideration (and mimi, it had occurred to me that messing with the sides might mess up the slot behavior - that's a good caution!) I have decided to postpone even thinking more about changing my saddle until I have my new bike and have the fit dialed in for it.

I did a little digging on the selle anatomica site and found that the memos they issue to their dealers have a ton of useful adjustment information, so I'll be looking at those very carefully as I'm getting settled on my new bike.