Great question! This is definitely a feature request I've heard before. 

While we don't currently offer this functionality, this would be a useful option for many of our sellers. Once someone does complete a sale from your online store, you do get access to their contact details. While this is pretty manual, you could consider sending them a follow up email clarifying any additional shipping details or information you'd like to provide.

As for your question regarding a more cutomizied pricing structure for shipping, I can also see how this would be useful. While we don't provide this feature with our store right now, you might check out BigCommerce, Weebly or Ecwid. We have partnerships with each of these ecommerce companies. Their offerings are pretty robust too. 

As a follow up, we're always working on improvements to our products, so I really appreciate you reaching out with your feedback. 

I look forward to seeing more of your posts on the community. 👍