Hi Robert,
Sorry for my late reply, Saturday, officially support we provide during Monday - Friday.
I want to show some trick regarding Metro grid and Pagination. Look at the screen, from our demo:
As you can see, after each 10 images layout is repeating. So, for 4 columns Metro layout need select 10, 20, 30, 40 etc pictures per page.
If you are using 3 columns layouts, layout will repeat after another number of images, but in any way, layout is repeating. So you need just to set correct number of images per pages.
and your layout will be "rounded"