You can use assign the newly created sidebar in any page and use the default on the default Blog page. An alternative would be to edit your siderbar.php and replace the “Aqua Sidebar” name of the default sidebar called with the name/id of your custom sidebar.

It looks like the reason that the blog posts page doesn’t display the sidebar you select for that page is because the post ID in sidebar.php is being returned as the post ID for the first post rather than the page itself. Here’s the code I used to fix the problem.

if(is_home()){//check if we’re on the blog posts page
global $wp_query;
$postid=$wp_query->queried_object->ID;
$sidebar = get_post_meta($postid, “boc_sidebar_set”, $single = true);
}

It seems to be working great (I can choose any sidebar for the blog posts page) so I thought I’d pass it on. Thanks again so much for taking the time to respond!