Hi Folks, I believe there are 3 ways to resolve this issue.
1) You can use product groups and exclude certain variants from being advertised (exclude by item ID).
2) You could delete the unwanted product variants within your Google Merchant Center account (Products > All Products)
3) You can remove the products from publishing to Google within the per-product Shopify channel settings, then use the Google Sheets method to create your own feed for that product and it's variants.
Hope that helps,
I have the same problem with Facebook and google shopify feeds. I think I will just export my data into access and strip it like that . I am working with my own custom products but also another supplier feed.
It seems the best option for both Facebook and google is to work with you own csv product feeds . Shopify fields don't map properly to Facebook fields and it just makes everything way to messy.
The hardest part of ecommerce I have found is getting everything right for Google and Facebook. I had a Canvas wrap flagged by Facebook for a policy violation "selling animals" It was a picture of a bird and had the bird name in the title. I also had another item flagged as "Alcohol" violation . It was a Canvas Wrap of a concrete horse and cart in a driveway .. GO FIGURE!
All I can suggest to make you shop easier to work with start with a very small dataset and get them through the system and then build slowly on that. I find I spend hrs in optimising my Catalog and product feed.