Good idea!
X3 doesn't require any settings for SSL, and is already fully compatible with SSL. As you can see, your X3 website already works fine under SSL:
https://gallery.kog.it/.
All you should do really, is
force SSL by redirecting all non-SSL traffic. I believe you can add this to .htaccess:
RewriteCond %{SERVER_PORT} 80
RewriteRule ^(.*)$ https://gallery.kog.it//$1 [R=301,L]
After adding the above, you should log in to X3 panel, click SAVE in settings (without changing anything). This makes sure cached pages are purged, and new pages will be created from SSL. Although your current website already "works" under SSL, several META tags link to non-SSL ... When you refresh your website from SSL, X3 will create links relative to
https protocol.
Although not strictly necessary, you should also change custom links that go to
http://gallery.kog.it, to avoid redirects.