The settings are stored at:
reg import the ready-made .REG files available here or
reg add the settings yourself and if required,
taskkill explorer.exe and relaunch it.
You can also use a utility like TSTbarSet, which allows you easy command-line access to most Taskbar-related settings:
TSTbarSet is a command-line utility to set common settings of the Windows Taskbar for individual user sessions and apply them immediately. Common settings include hiding the clock on the taskbar, hiding Taskbar itself, and setting the position of the taskbar within the user session.
This utility was written for the purpose of allowing an administrator the ability to deploy common Windows Taskbar settings for multiple users. TSTbarSet allows these settings to be implemented at anytime during a users session without the need to logoff and logback on again.