But the market research had been done and the decision fell on the GoPro Hero 4 Session. Smaller than the normal GoPro and less advanced and thus also less expensive (half the price; 220 EUR); bought it on Tuesday at Coolblue and got it delivered yesterday; and ready for a test on my evening ride today.
I used the timelapse mode with a 10 seconds interval; for a ride of 2 hours 15 minutes this resulted in 812 photos. A small selection (unedited photos) can be found in the slideshow below. All in all nice results 🙂
Creating the timelapse playback (with GoPro Studio) I choose to reduce it to 25% of the normal speed.