I have been riding a C17 carved most of this year on my gravel bike. Love it! I did ride a C15 carved for a while but it was too narrow after about 65 miles. The LBS just got in two of the three widths of the C13 carved. I can already tell the I will be "needing" one of those in the 158mm width. What I really like about the new C13 is the flat top (front to rear). This should prevent the need to have the nose up so much on this saddle compared to the C17.

The C17 has the slight rise in the rear which makes it necessary to raise the nose quite a bit to settle into a good position on it without getting pushed forward all the time. Not necessarily a huge problem for day to day riding but I did run into an issue when I put aero bars on my gravel bike for a 250 mile race. I had to lower the nose to get a good fit for being in the aero bars which changed the comfort level when on the hoods. I think the C13 is going to be great for this type of setup. The 150 grams lighter isn't going to hurt either!

I have been through all kinds of saddles and ridden a long races on many of them. My favorite still, but least durable, is the Terry FLX womens saddle (I'm a guy but it fits so awesome). I got tired of buying a new saddle every 12-18 months due to wearing out the leather on that saddle. The C17 carved is by far my favorite for durability and comfort all in one package. It's not for everyone and some people just can't stand the nose up look of the saddle on a bike. The added suspension effect of the rubber top is nice on gravel as well.