We are a manufacturer of aluminum roof vents which we sell retail on our site, and also sell through large online outlets like Home Depot (not all of our products). We're now selling through Google Shopping. The GTINs used by Home Depot include both colored (up to 6 choices) and uncolored products.
On our own site, we have many more colors available, but we only list our products as (woocommerce) 'Simple' products, so the GTINs are technically the uncolored product. As part of our shopping cart, customers can specify one of 30+ colors.
The side effect of this is that when a Home Depot shopping ad is shown for a colored vent, the list of available shops doesn't include us. For the unpainted vents, we are in the list, usually at the top (I think because we're the registered manufacturer). I want to be included in those shopping ads.
So the question is, how do I include the GTINs with color in the schema for our website, without having to register GTINs for all of our color variations? I'd rather not use the variable/variations feature because it seems overkill to balloon our product catalog from 500 products to 15000. If I created new product pages for the vents Home Depot carries, then perhaps I can use Canonical to indicate it is really the same as the unpainted product. I'd rather include the painted GTIN variations on the one page for the unpainted product.
All insights appreciated.