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Design and Skin Customization
the problem in your one is that "video_...." is only going to be a key on uploaded videos, try using a key that is on all of them or using the || which is OR but that will make it heavier on your system. May be ok if its not pulling a ton per page.
so try search1="video_rating_overall_average_count > 3 || youtube_rating_overall_average_count > 3"