lol no looping scripts not diving by zero lol. pretty basic stuff here.
"So I can't change the order: excerpt, content, gallery..."
Right you can't change the order with this currently.
"If I wanted a layout just like the Wide Layout, with that nice header, then the gallery and then the rest, using the shortcodes, would I then have to add a regular WP pages and then add the shortcodes? can't see a shortcode for the content and extra fields, and I'm sure the header would not be visible if not within the pockets template."
The layout is chosen by picking a layout. Once you create a Wordpress gallery for that post, the gallery shows. If you don't the gallery doesn't show. The text is taken using the_content(). In a single post, there's a area you can enter anything into, like shortcodes. The header image, is the featured image. Everything is using Wordpress.