How do I change xsetwacom and make the settings stay on startup?

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.