One Blog Installation, Two options sets

I want to setup a test blog on a subdomain of my site, and I want it to have the same data as the main blog, BUT I want to have different options for the second blog.

I have read that you can force WP to look at a different Users tables by using the following in the wp-config.php file, what would I use to change the options table?

define('CUSTOM_USER_TABLE', 'wp_users');
define('CUSTOM_USER_META_TABLE', 'wp_usermeta');

Would I use this:

define('CUSTOM_OPTIONS_TABLE', 'wp2_options');

in the second wp-config.php file or something different?