Change Omega4 Layout Based on Content Type via template.php
As per referenced question I would go with something like the following:

function THEMENAME_omega_layout_alter(&amp;$layout) {
  if (arg(0) == 'node' &amp;&amp; is_numeric(arg(1))
      &amp;&amp; $node = node_load(arg(1))) {
        switch ($node-&gt;type) {
          case 'article':
            $layout = 'article';
            break;
          case 'blog':
            $layout = 'blog';
            break;
          default:
            $layout = 'default';
        }
   }
}