I know this has been asked before but I don't feel like it was accurately answered.
My store has many different products and I use ShipStation to manage my shipping.
The sizes of these items vary from tiny things that go into padded envelopes to box sizes that range from 16x4x4 to 16x8x8.
I have all my carriers setup via ShipStation but Shopify only allows you to select 1 default box size.
What's the "best" process for handling and making sure every time I add a new product the shipping rates the customer is seeing are really accurate? Right now I am overestimating weights on things but for the future, I want to make sure things are accurate. Also when they add multiple products to the cart of different sizes, how do I know they're getting an accurate rate?