Does this still work? Shopify no longer seems to show the google columns.
I can download a .csv containing all products with a specific type of error from Google Merchant Centre but see no way to upload the corrected .csv. Most of my products come in 10 colours and 10 sizes so google sees these as 100 different products and it’s just so time consuming to try and fix one by one. Adding feed rules have helped a bit but still can’t get it all to work.