Generally, YouTube videos follow the 9/16 ratio (56.25). So, kindly do not change the default ratio value to avoid the black spaces around the video.
I understand the player is big on your website. Because it scales 100% to its container element. So, the better solution would be to set a max width for the gallery wrapper element. Kindly try adding the following CSS code under the “Appearance => Customize => Additional CSS” menu from your WordPress Admin Dashboard,
.ayg-theme-classic {
max-width: 720px;
margin: auto;
}You simply need to adjust the “max-width” value on the code above as you need.
Also, I really appreciate your suggestion about loading the player only after the user had clicked a thumbnail. I promise that our next version can do this. Kindly be patient.
Note: I see another issue on your website. The videos are not playing when clicking on a thumbnail from the gallery due to a conflict with the “WP Rocket” plugin. Kindly refer to this article https://docs.wp-rocket.me/article/15-disable-lazy-load-on-specific-images and exclude our plugin images from lazyloading.
The CSS class name used by our plugin for images is “ayg-thumbnail-image”.
Hope this solved your issue!