Layout for galleries and number of posts

1 – Why does the Gallery theme only show 10 custom post types at a time? It is the same for the grid on the home page as well as the category pages. How do I adjust the number? 10 creates an unbalanced layout. Weird.

2 –

I am assuming that the example page here is using the standard wordpress gallery and the page template gallery. When I try to do the same I can’t get the gallery to work.

I tried gallery shortcodes from here with no luck.

Whats the magic?