Hi, I've also just purchased the 2000. I have about 10 hours on it and spent most of my ride time trying to get a good rear set-up. The tech at my LBS ( Cannondale factory trained ) told me to start at 70% of my body weight ( currently 170# ) and go from there. I found this (120#) to be to soft for me and bumped it up to 135# and so far I have to say it feels pretty good, but obviously a lot different than my hardtail so it's taking a while to get used to.
I'm with cyccommute and have been advised that the sag is a better guideline but I'll be damned if I can set the thing up...
As far as the 3 position switch settings ,centre is neutral,right is soft, left is firm. I'm still playing with that one and pretty much keep it on firm.
I hope this helps