First, let me say thank you for developing this plugin. This issue is one that has been bothering me greatly. So I installed the plugin via wp-admin, and these are my observations:
1. Good: my scores on both desktop and mobile on Google rose a few points (about 5 points in each case).
3. Not Good: There is some strange code on the header of the site (please see screenshot below).
My site is http://www.churchpatrol.com/
If you are able to fix it and get to work as advertize, this would be a lifesaver!