I’m not certain if I know what you want to achieve, but created layout can be:
a) Viewed in the layout designer - you can press ‘arrows’ there to cycle through other items in the same region, perhaps that would be helpful?
b) Previewed in the new window - browser preview that will show your layout for it’s whole duration
c) Scheduled to the display player
You can also see image thumbnails if you open region timeline.