Implementing stock control for delivery periods annotation required quite a bit of programing in Liquid to dynamically change the stock counter when different sizes are chosen. To say that it is an area that Shopify itself has neglected to document is not strong enough. They made main components obsolete but documenting is still not changed after more than two years. I placed questions in both Shopify and Stackoverflow forums and received no answer. In the end, problem solving hat on and eureka. It is done. A few more tweacks and will be redy for 100% launch.