UPD.
Just read about warnings in google merchant center support:
“Warnings: These are issues that could negatively impact the performance of your ads and will likely lead to item or account suspensions in the future unless you resolve the issue.”
I think making the ability to set up attributes, size and etc on plugin settings is crucial.
Also, making an additional field in the product category for google_product_category would be great. An automatic appointment isn’t always working as intended.
