Hello Restless:
It appears your comment went unnoticed, as the thread continued on with a discussion of version #'s. I too am frustrated by Google insisting my content is too wide for mobile. I too use variants that are 320px, 480px, 960px, and even 1200px, but Google keeps reporting errors related to content width, viewport not set (but it is!), etc. So, I'm wondering if you did finally receive any resolution from your comment. Thanks for posting.