ISSUE: LTK widgets do not look the same as in your demos
The EmPress Shop the Post plugin does not control any aspect of how your LTK Shop the Post widgets will format. It only provides a field to inject your widgets into various places around your site, so users can see the widgets without clicking into a post.
Instead, you can control the size of product thumbnails by changing the Product Image size when you build out your widget within the LTK Creator platform. Enlarging the product image size when you build the widget may help, as LTK's code may naturally adjust for padding/spacing based on the product image size.
Where applicable, our demos all feature LTK widgets, and we tend to size our product images at 125-150px, which makes the products appear a little bigger than the default.