This is designed to show 10 posts on each of the pages after the home/blog page when the home page only shows 5 (because if you just use posts_per_page=10 without the offset you will lose the most recent posts numbered 6-10 in between the first and secon home/blog paged).

You can tweak it to different numbers, but you'll need to change the maths (10 * ($page - 1) - 5) to suit.

function custom_queries() {
    global $query_string;
    if (is_home()) {
        $page = get_query_var('paged');
        if ($page > 1 )
            $offset = 10 * ($page - 1) - 5;
        else
            $offset = 0;
        if ($page > 1 )
            query_posts($query_string . "&posts_per_page=10&offset=$offset");
    }
}
add_action('thesis_hook_before_content', 'custom_queries');