[WPMU DEV Dashboard] Total Saving

Good Day,
after running smush pro I ended up saving only 27.5MB and Accordingly with google speed test the images can be further compressed.
Our goal is to improve the overall website speed without having visible changes in the quality of our full width images. Do you have any suggestion on how we can get the most out of Smush Pro in terms of compressing full width images, but without losing to much in quality?
Regards, Mattia