MAgento configurable products and Google Shopping Feed

Hi,

I have installed a Google Shopping Feed extension and it is working fine, but... It seems that I shouldn't include 'Configurable Products' in my shopping feed and that I should include only the variants of that configurable product.

So it has been suggested to me that I should change the 'Visibility' of the variants from 'Not Visible' to 'catalog, search or catalog'

I know at the moment if I don't change the visibility then Google Shopping just picks up 404 errors on the variant products, but what I am trying to find out is if this is the correct process?

I actually can't think of another way to getting Google to pic up the variants, but I am concerned if I change all the products to 'Visible' then all my variants will display on my front end of website and therefore create multiple duplicate content issues and other unknown (as yet) issues.

Any guidance would be great.