Memento Pro will be able to read your image rankings as set in Adobe Lightroom, and use these to feature better ranked images more prominently in your layouts. Higher ranked images will automatically be placed into larger image frames when using any auto-layout tool.
Consult the following tutorial video here to learn more.
To further enhance your best photos, use the Featured image setting for the image frame. Select an image, and toggle the Featured tab over it.
The frame properties will conform to the selected Style of the page.
Consult the article on Styles to learn more about setting up custom attributes sets that you can apply to one or all of your project's pages.