Debian Stretch: How do I make Wayland the default?

I am running Debian Stretch 9.1 with GNOME 3 as the desktop environment and GDM for session management. I tried GNOME on Wayland from GDM (gear icon) and it works very well. I would now like to configure an autologin to GNOME on Wayland.

I am able to log into GNOME on Wayland by default without autologin. I am able to autologin but only on GNOME on X. The latter is my current configuration.

Any pointers would be very much appreciated.

What didn’t work

After reading Q&As from other distros I tried adding the following to /etc/gdm3/daemon.conf in the daemon section (one at a time). None of these options works. DefaultSessions does not appear to be an option in /usr/share/gdm/gdm.schemas.

DefaultSession=gnome-wayland.desktop
DefaultSession=gnome-wayland
DefaultSession=/usr/share/wayland-sessions/gnome-wayland.desktop

System info

$ cat /var/lib/AccountsService/users/marc
[User]
Language=en_US.UTF-8
XSession=gnome-wayland
SystemAccount=false

$ ls /usr/share/xsessions/
gnome-classic.desktop  gnome.desktop

$ ls /usr/share/wayland-sessions/
gnome-wayland.desktop

$ cat /etc/gdm3/daemon.conf 
[daemon]
AutomaticLoginEnable = true
AutomaticLogin = marc

The contents of /usr/share/xsessions/gnome.desktop and /usr/share/wayland-sessions/gnome-wayland.desktop only differ in the Name parameter. The other parameters (except Comment) are as follows.

Exec=gnome-session
TryExec=gnome-session
Icon=
Type=Application
DesktopNames=GNOME