Hi Dynamicweb
What about showing the variants under the produkt. It's best practice and used on most fashion ecommerce sites, zalando, boozt, ellos and so on and gets thumbs up in many ux analytics.
I can see the data is already in the datafeed, but I understand there must be some kind of configuration to setup if and what variant you want to show and what you don't what to show.
On Zalando Color is shown but shoesize is just a label https://www.zalando.dk/herresko/ indicating that there is multiple sizes.
/Kim