$ defaults read -g | grep mouse
    "com.apple.mouse.doubleClickThreshold" = "1.1";
    "com.apple.mouse.scaling" = "2.5";

defaults write -g com.apple.mouse.scaling -float 2.1

tell application "System Preferences"
    reveal pane "com.apple.preference.mouse"
end tell
tell application "System Events" to tell process "System Preferences"
    set value of slider 3 of window 1 to 9.0 -- maximum, minimum is 0.0
end tell
quit application "System Preferences"