I added a question to the above post regarding Shipping Rate Request after you had already replied.
It's asking for the package weight, type, size, length, width and height. Every package will be different depending on what is ordered. If I have each product's size and weight specifications in the shopping cart, will eCart figure the packaging out dynamically based on the specified carrier? Not sure how it can do this, particularly for box size, as it doesn't know how the items will be arranged - for example, if they can be folded or compacted.