How to trigger workflow for a specific product size ordered after shipment delivered

I’m trying to set up a workflow to be triggered with the following criteria:

1. Ordered a specific size
2. To trigger only after the product has been delivered (i.e. Shipment Delivered metric via shopify)

I currently have my workflow trigger as follows:

• Trigger: When someone Ordered Product
• Trigger filters: Variant option: Size equals [Size]
• Profile filters: Delivered Shipment at least once since starting this flow

I’m guessing no one will receive the emails from this flow because all the criteria will need to be fulfilled at the same time and Delivered Shipment usually happens a few days later? How should I set up the workflow instead? I tried setting the trigger as ‘Delivered Shipment’ but I can’t set the Trigger Filter to include the size variant. 

Any help would be much appreciated - thank you!