I have a seatpost from a Canyon Dndurace AL 7.0 from 2016. The seatpost has a saddle clamp consisting of two parts. The lower part has one long end and a shorter one. I can rotate both parts of the clamp. Which direction of the lower part should be forward facing? Also was I right in matching the upper part to the lower part?
It seems that from their photos, you have the correct setup.
Structurally, it also makes sense as the longer rear of the clamp supports the part of the saddle that you'll sit on, though it would also make sense to rotate the top clamp to assign its beefier 'claw' to the front, which also undergoes a larger vertical cantilever force.
If you want to be sure, you can contact Canyon themselves. As for my opinion, I'd just rotate the top clamp for the aformentioned reasons and it'll likely be good to go.