Write xsetwacom commands into ~/.xinitrc.
xsetwacom deliberately doesn't keep settings between X server restarts. The easiest (and safest) way to get stable settings is to just stick your list of xsetwacom commands into a shell script and add it to your startup applications.
Alternatively, you can bypass xsetwacom comletely and put your tablet settings in /usr/share/X11/xorg.conf.d/50-wacom.conf -- the "wacom" manpage lists the option lines. As always, be careful and remember that a poorly formed conf can render your device unusable.
No luck from any, the script is running as I'm creating an arbitrary test file in my home directory but the wacom settings aren't saved
– blented Oct 20 '16 at 05:04gedit ~/.xinitrc
then writexsetwacom --set 11 Mode Relative
, save the file, restart. – Maarten Nov 25 '18 at 12:40