I have tweaked my mouse sensitivity to be just right, and swapped the mouse buttons since I use it left-handed. This was done using the user "Mouse & Touchpad" settings in Gnome.
I'd like this to apply to the login screen and all other user sessions (since they're all mine as well anyway). I'm using Gnome 3.8 under 13.10, but other sessions might use Unity or XFCE.
How do I apply my session mouse settings globally?