It looks like you're addressing me ;-)
If you want to modify this code snippet:
add_action( 'wp_logout','go_home' );
wp_redirect( home_url() );
you can replace the
home_url() part with your custom page URL:
but I wouldn't recommend hardcoding the landing page, if it's an internal page.
You can try to construct the landing page with various WordPress functions:
You have for example
get_permalink() and extra input parameters to
home_url(). Then there's
get_post_type_archive_link(), ... etc.
If you explain what kind of landing page you have in mind (page, post, archive, custom, external) then I can expand it further.