I got the syncevolution method to work 
But it took quite some time to get things straight.
- The script needs another variable declaration
- after the line with “CAL_URL=…” add another with “CONTACTS_URL=…”
- Initially I used spaces in “CALENDAR_VISUAL_NAME” and “CONTACTS_VISUAL_NAME”, but that seems to break the script
- I had to install my self-signed certificate - saved as *.crt - first (after storing it in the home dir):
sudo mount / -o remount,rw
sudo cp <mycertificate>.crt /usr/share/ca-certificates/
sudo dpkg-reconfigure ca-certificates
sudo mount / -o remount,ro
Not sure if that survives system updates…
Edit: I saw that someone forked the gist and added the two necessary changes. The updated one can be found at https://gist.github.com/vanyasem/379095d25ac350676fc70c42efe17c8c