In the past I’ve used a seatpost with 7x10 clamps to secure a saddle with 7x9 rails. It cut the rails up a bit with the proper torque so I ended up having to get a new seatpost that had 7x9 clamps. Well I just ordered a Madone Friday that should be at my LBS in a day or two which I have 7x10 clamps for. Being Trek, a new seatpost isn’t much of an option I know of although maybe I didn’t look hard enough. I’m afraid I’ll run into the same issue again so looking to see if others have overcome this difference somehow or if maybe the Madone seat clamps doesn’t cause problems with 7x9 rails. A new saddle is the easiest option on paper although it took me quite some time to find what I like and I hate ANY padding making the choices even fewer. If I knew I could take a Power saddle and rip the padding off that would be the easiest in my opinion, bit of an expensive experiment though.
Did you check with Trek (Bontrager?) since the seatpost is exclusive they might have an adapter. You have a Fizik carbon rail saddle?
actually i googled it and it appears you need this - Bontrager Rotary Head Seatpost Saddle Clamp Ears
shocked that I got here before @mcneese.chad
Mike
Savour it 
Cobb (Speed and Comfort) Carbon One.
Per Trek that’s not compatible with the Madone seat mast nor do they make one in house. That’s for the Emonda style seat mast.
Ahhh I see - I did some additional googlefu and am stumped as well.
Do they sell a 7 x 10 metal rail version of your saddle? Not ideal but better than clamping down on a carbon saddle and hoping for the best.
also Mitch form Trek is on here as well as Slowtwitch - might drop him a line
Guessing you’re talking about the San Remo or the new Pro SR. Could’ve sworn I test rode the San Remo then got the 151 instead before also buying the Carbon One. Still have the 151, just prefer the carbon top (no padding). 151 is actually the saddle with the marked up rails I mentioned. At any rate, I appreciate you looking at Cobb’s selection! If I can’t solve it I’ll probably just get a Power saddle with round rails.
Happen to know Mitch’s username on either forum? Can’t say I’ve seen the name.
[Mitch@Trek] on Slowtwitch and there is Trek link " [Hey SlowTwitch - Trek Community Manager Here!" in the main forum where he responds almost daily
@MitchatTrek on here, but I don’t see him as often